A06-000009 R7 - Welding, Fab. & Inspection Req. Mill Shells

______________________________________________________________________________ WELDING, SPEC. NO. A06-000009 REV 7 FABRICATION, PAGE: 1 of 18 AND INSPECTION APPROVED BY: VS REQUIREMENTS ISSUE DATE: 10 March 2004 MILL SHELLS SUPERSEDE DATE: 11 Oct 2000 1.0

SCOPE This specification defines welding, fabrication, and inspection requirements for grinding mills.

2.0

PURPOSE The purpose of this document is to provide a detailed specification for suppliers, contractors, designers, buyers, etc., and to outline specific requirements and code references applicable to grinding mills.

3.0

STANDARDS AND CODES

3.1

This specification contains proprietary techniques that have been developed by Engineering.* This specification shall govern in case of conflict with any code or standard.

3.2

This specification has been prepared using AWS D1.1 - Structural Welding Code Steel, as a reference. In the case of workmanship or procedures not covered by this specification, AWS D1.1 shall be used. This specification is compatible with AWS D1.1 1996 and later editions.

3.3

All prequalified joint welding procedures to be used shall be prepared by the manufacturer, contractor, or fabricator as written weld procedure specifications (WPS), and shall be available to those authorized to examine them.

3.4

Changes to welding methods or standards referenced herein, as well as welding procedures not conforming to the requirements of this specification, shall be submitted to Division Engineering/Quality Assurance for approval before being used in production, and are subject to qualification. (Paragraph 8.3.2.1)

3.5

Compliance with all requirements of this specification shall be demonstrated to the satisfaction of Division Engineering/Quality Assurance.

3.6

Non-compliance with any requirement of this specification shall be documented and approved by Division Engineering/Quality Assurance.

4.0

UNITS OF MEASUREMENT

Within this specification, values are stated as US Customary units and SI units. SI units are shown in parentheses. The values stated in each system are not exact equivalents. Combining values from the two systems may result in nonconformance with this specification. _____________________________________________________________________________ *Where the terms “Engineering,” “Quality Assurance” or “Division Engineering/Quality Assurance” are used within this specification, it shall be understood to mean Metso Minerals Grinding Division Engineering, Metso Minerals Grinding Division Quality Assurance or Metso Minerals Grinding Division Engineering/Quality Assurance, respectively.

______________________________________________________________________________ WELDING, SPEC. NO. A06-000009 REV 7 FABRICATION, PAGE: 2 of 18 AND INSPECTION APPROVED BY: VS REQUIREMENTS ISSUE DATE: 10 March 2004 MILL SHELLS SUPERSEDE DATE: 11 Oct 2000 5.0

WELDER AND INSPECTOR QUALIFICATION

5.1

All welders, welding operators, and tackers (even tack welds, which are completely removed) to be employed under this specification shall be qualified in accordance with AWS D1.1, Section 5 or ASME Section IX or foreign equivalent.

5.2

Personnel performing nondestructive testing (NDT) shall be qualified in accordance with the American Society for Nondestructive Testing (ASNT) Recommended Practice SNT-TC-1A, December 1988 edition. Foreign equivalents will be considered by Division Engineering/Quality Assurance.

6.0

BASE METALS

6.1

All base metals shall be ASTM A36, ASTM A516 Grade 60, or foreign equivalents*. *The foreign equivalents are to be fully compatible with ASTM A36 or A516 Grade 60, including silicon (Si) chemistry.

6.2

The following materials shall meet the requirements of Spec. No. A06-000012 Specification for Lamellar Tear-Resistant Steel. ` a.

All flange material.

b.

All cone plates. Cone plate for bolt-on mill heads may be released from this requirement by Division Engineering.

c.

Trunnion or filler ring mounting rings.

6.3

For all base metals under this specification, certified chemical and mechanical test reports are required from the supplier. Maximum carbon (C) content is not to exceed 0.30 percent (0.30%).

6.4

TRACEABILITY

6.4.1

The mill shell shall have a unique identification number, so that all operations, such as heat treatment, inspections, repairs, etc., can be traced and identified to the individual component.

6.4.2

The identification number shall always be on the component and all corresponding records. If steel stamping is used for identification LOW STRESS stamps must be used.

______________________________________________________________________________ WELDING, SPEC. NO. A06-000009 REV 7 FABRICATION, PAGE: 3 of 18 AND INSPECTION APPROVED BY: VS REQUIREMENTS ISSUE DATE: 10 March 2004 MILL SHELLS SUPERSEDE DATE: 11 Oct 2000 7.0

WORKMANSHIP

7.1

PREPARATION OF BASE METALS Surfaces and edges to be welded shall be smooth, uniform, and free from fins, tears, cracks, and other defects which could adversely affect the quality or strength of the weld. Surfaces to be welded shall be free from loose scale, rust, slag, grease, moisture, or other material that will prevent proper welding. All mill scale shall be removed from all surfaces on which tee or corner welds are to be made. Surfaces within 6 inches (152 mm) of any weld location shall be free of any paint or other material that would prevent proper welding or produce objectionable fumes.

7.1.1

Thermal cutting processes are limited to arc-cutting and oxyfuel gas processes.

7.1.1.1

The roughness of thermal cut surfaces shall be per code.

7.2

FIT-UP

7.2.1

If root openings do not permit fit-up within limitations of approved weld procedures, set forth in paragraph 8.3 of this specification, the procedure necessary to bring the material within the limit, shall be approved by Division Engineering. The use of permanent filler bars to compensate for poor fit-up is prohibited.

7.2.2

ALIGNMENT

7.2.2.1

Abutting parts shall be carefully aligned.

7.2.2.2

Where parts are effectively restrained against bending due to eccentricity in alignment, an offset not exceeding 1/8 inch (3 mm) is permitted as a departure from the theoretical alignment. In correcting misalignment in such cases, the parts shall not be drawn into a greater slope than 1/2 inch in 12 inches (4.25 mm in 100 mm). Measurement of the offset shall be based on the centerline of the parts, unless otherwise specified on drawings or approved by Division Engineering.

7.2.2.3

Temporary attachments welded to sections, members, or components to facilitate assembly, alignment, etc., shall be removed after the operation is complete, and the surface shall be restored to the required contour and thickness. Areas from which attachments have been removed shall be inspected by methods covered under this specification, and are subject to the same requirements as permanent welds.

7.2.2.4

If local heating of the plate is required in order to obtain proper alignment at any stage of fabrication, a detailed procedure must be submitted to and accepted by Division Engineering prior to use.

______________________________________________________________________________ WELDING, SPEC. NO. A06-000009 REV 7 FABRICATION, PAGE: 4 of 18 AND INSPECTION APPROVED BY: VS REQUIREMENTS ISSUE DATE: 10 March 2004 MILL SHELLS SUPERSEDE DATE: 11 Oct 2000 7.2.2.5

Radial offset of abutting edges shall not exceed 1/8 inch (3 mm). (See Sketch 7.2.2.5) Circumferential and Longitudinal Flange to Shell

±1/8 Inch (3 mm) Maximum

Inside Surface Butt Joint

±1/8 Inch (3 mm) Maximum

Inside Surface Contour Flange

Inside Surface

±1/8 Inch (3 mm) Maximum

SKETCH 7.2.2.5 7.2.2.6

Cone Plates and Trunnion Rings (See Sketch 7.2.2.6) Cone Plate and Trunnion Ring

0° 30' Maximum 0° 30' Maximum Inside Surface Inside surfaces of cone plate and trunnion ring must be parallel after welding. Machine inside surface of trunnion ring during final machining, if necessary, to obtain parallelism. (Notify Division Engineering/QA before machining to obtain parallelism.) SKETCH 7.2.2.6

______________________________________________________________________________ WELDING, SPEC. NO. A06-000009 REV 7 FABRICATION, PAGE: 5 of 18 AND INSPECTION APPROVED BY: VS REQUIREMENTS ISSUE DATE: 10 March 2004 MILL SHELLS SUPERSEDE DATE: 11 Oct 2000 7.2.3

SHELL BRACING Bracing shall be per drawing. Any variations must be submitted to Division Engineering/ Quality Assurance for approval before use.

7.3

ASSEMBLY OF MATING PARTS

7.3.1

The maximum allowable step across the longitudinal flanges of the shell segments is 1/8 inch (3.2 mm), and may be achieved by flange grinding in the step. (See Sketch 7.3.1) Longitudinal Flange to Longitudinal Flange Joint

1/8 Inch (3.2 mm) Maximum

1. Inside of flange may be ground to achieve the 1/8 inch (3.2 mm) maximum step.* 2. Division Engineering/QA must be notified before grinding. * When grinding to correct misalignment or provide smooth transitions, plate thickness shall not be reduced by more than 1/32 inch (1 mm). SKETCH 7.3.1 7.3.2

When the liners cross the flange joint, the maximum allowable across-the-cans step is 1/8 inch (3.2 mm). When the liners do not cross the flange joint, the maximum allowable across-the-cans step is 7/32 inch (5.5 mm). This will be a maximum for all tolerance accumulation. This must be considered for each can before the fabrication process starts. (See Sketch 7.3.2) Circumferential Flange to Circumferential Flange Joint

7/32 Inch (5.5 mm) Maximum

1. Inside of flange may be ground to achieve the 7/32 inch (5.5 mm) maximum step.* 2. Division Engineering/QA must be notified before grinding. *When grinding to correct misalignment or provide smooth transitions, plate thickness shall not be reduced by more than 1/32 inch (1 mm). SKETCH 7.3.2

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7.4

WELD PROFILES

7.4.1

Weld profiles shall be in accordance with AWS D1.1, Section 5.24.

7.4.2

Groove welds shall be made with slight or minimum reinforcement, unless otherwise specified. The reinforcement shall not exceed 1/8 inch (3 mm) in height on the inside and outside surfaces, and shall have gradual transition to the plane of the base metal surface. Grinding of weld reinforcement shall be per drawing.

7.4.3

Welds to be ground per drawing shall have a maximum surface finish of 125 µinches (3.2 µm). The final grinding passes will be done with equipment to minimize the heating of the weld and base metal.

7.4.4

Surfaces required to be flush shall be finished so as not to reduce the thickness of the thinner base metal or weld metal by more than 1/32 inch (1 mm), and must blend smoothly into the plate surfaces, with transition areas free from edge weld undercut.

7.4.5

Undercut shall be no more than 0.01 inch (0.25 mm) deep if the weld is transverse to the primary stress direction in the part that is undercut. Undercut shall be no more than 1/32 inch (1 mm) deep if the weld is parallel to the primary stress direction in the part that is undercut.

7.5

REPAIRS

7.5.1

REPAIRS OF WELDS

7.5.1.1

Welds that are found unacceptable in accordance with this specification or by contract requirements, shall be repaired within the limitations of this specification.

7.5.1.2

A repair procedure shall be developed and utilized by the manufacturer.

7.5.1.3

A repaired or replaced weld shall be retested by the nondestructive test method (NDT) originally used, and the same technique and acceptance criteria shall be applied.

7.5.1.4

A report shall be submitted for each NDT inspection performed, including repairs.

7.5.1.5

For repairs after stress relief, see paragraph 10.4.1 of this specification.

7.5.2

REPAIRS OF BASE METAL

7.5.2.1

After stress relief, any repair of base metal requires Division Engineering/Quality Assurance approval.

______________________________________________________________________________ WELDING, SPEC. NO. A06-000009 REV 7 FABRICATION, PAGE: 7 of 18 AND INSPECTION APPROVED BY: VS REQUIREMENTS ISSUE DATE: 10 March 2004 MILL SHELLS SUPERSEDE DATE: 11 Oct 2000 7.6

PEENING The use of manual slag hammers, chisels and lightweight vibrating tools for the removal of slag and spatter is permitted and is not considered peening.

7.6.1

MANUAL PEENING

7.6.1.1

Controlled peening may be performed to minimize distortion only when authorized by Division Engineering.

7.6.1.2

All Controlled peening shall be performed per code and a procedure written.

7.7

CLEANING

7.7.1

Before welding over previously deposited metal, all slag shall be removed, and the weld and adjacent base metal shall be brushed clean. This requirement shall apply to successive layers, as well as to successive beads and the crater area when welding is resumed after any interruption.

7.7.2

On completed welds not requiring grinding or finishing, all spatter shall be removed and the finished welds wire brushed, if necessary, to provide a clean surface which is free of scale, slag, etc.

8.0

WELDING

8.1

WELDING PROCESSES The following welding processes are permitted, as defined by this specification. Shielded Metal Arc Welding (SMAW) Flux Cored Arc Welding (FCAW) Submerged Arc Welding (SAW)

8.1.1

ELECTRODES FOR SHIELDED METAL ARC WELDING (SMAW) a.

Electrodes for shielded metal arc welding (SMAW) shall conform to the requirements of AWS A5.1 - Specification for Carbon Steel Electrodes for Shielded Metal Arc Welding.

b.

When requested by Division Engineering, the contractor or fabricator shall furnish the electrode manufacturer's certification stating that the electrode will meet the requirements of classification or grade, as set forth in this specification.

______________________________________________________________________________ WELDING, SPEC. NO. A06-000009 REV 7 FABRICATION, PAGE: 8 of 18 AND INSPECTION APPROVED BY: VS REQUIREMENTS ISSUE DATE: 10 March 2004 MILL SHELLS SUPERSEDE DATE: 11 Oct 2000 8.1.2

8.1.3

LOW HYDROGEN ELECTRODE STORAGE CONDITIONS a.

All electrodes having low hydrogen coverings conforming to AWS A5.1 shall be purchased in hermetically sealed containers or shall be dried for at least two (2) hours between 500 °F (260 °C) and 800 °F (430 °C) before they are used. Immediately, after opening hermetically sealed containers or removal of the electrodes from the drying ovens, electrodes shall be stored in an oven and held at a minimum of 250 °F (120 °C). Electrodes that have been exposed for extended periods shall be redried in accordance with AWS D1.1, Section 5.3.2.4, or the electrode manufacturer’s recommendations.

b.

Electrodes that have been wet shall not be used.

ELECTRODES AND SHIELDING GAS FOR FLUX CORED ARC WELDING (FCAW) a.

The electrodes and shielding gas accepted by this specification are: i.

E70T-1, E71T-1, E70T-5 for flux cored electrodes per AWS A5.20 Specification for Carbon Steel Electrodes for Flux Cored Arc Welding.

ii. Welding grade carbon dioxide (CO2) or C-25 having a dew point of -40 °F (-40 °C) or lower. b.

8.1.4

SUBMERGED ARC WELDING (SAW) a.

8.1.5

When requested by Division Engineering, the contractor or fabricator shall furnish the electrode manufacturer's certification stating that the electrode will meet the requirements of classification or grade, as set forth in this specification.

Submerged arc welding may be performed with a single electrode. The approval of Division Engineering/Quality Assurance is necessary before more than one single electrode, one or more parallel electrodes, or combinations of single and parallel electrodes may be used. Division Engineering/Quality Assurance approval is also necessary for the welding of more than one joint simultaneously.

ELECTRODES AND FLUXES FOR SUBMERGED ARC WELDING (SAW) a.

The bare electrodes and flux used in combination for submerged arc welding of steels shall conform to the requirements in AWS A5.17 - Specification for Carbon Steel Electrodes and Fluxes for Submerged Arc Welding.

b.

When requested by Division Engineering, the contractor or fabricator shall furnish an electrode and flux manufacturer's certification stating that the electrode and flux combination will meet the requirements of the classification or grade, as set forth in this specification.

______________________________________________________________________________ WELDING, SPEC. NO. A06-000009 REV 7 FABRICATION, PAGE: 9 of 18 AND INSPECTION APPROVED BY: VS REQUIREMENTS ISSUE DATE: 10 March 2004 MILL SHELLS SUPERSEDE DATE: 11 Oct 2000 8.1.6

CONDITION OF FLUX a.

The requirements of this section are necessary to assure that the flux is not a medium for introduction of hydrogen into the weld due to absorbed moisture in the flux. Whenever there is a question about the suitability of the flux due to improper storage or package damage, the flux should be discarded or dried in accordance with the manufacturer’s recommendations.

b.

Flux used for submerged arc welding shall be dry and free of contamination from dirt, mill scale, or other foreign material.

c. 8.1.7

Flux that has been wet shall not be used.

ALTERNATIVE WELDING PROCESSES Any welding process not specifically covered by this specification requires Division Engineering/Quality Assurance approval.

8.2

PREHEAT AND INTERPASS TEMPERATURES

8.2.1

Preheat shall be in accordance with the applicable welding procedure specification, but in no case less than that specified in Table 8.2.1. THICKNESS - inches t ≤ 3/4 inch 1½ inches ≥ t > 3/4 inch 2½ inches ≥ t > 1½ inches 5 inches ≥ t > 2½ inches 8 inches ≥ t > 5 inches t > 8 inches

PREHEAT - °F None* 70°F 150°F 225°F 300°F 350°F

THICKNESS - mm t ≤ (19.0 mm) (38.1 mm) ≥ t > (19.0 mm) (63.5 mm) ≥ t > (38.1 mm) (127.0 mm) ≥ t > (63.5 mm) (203.2 mm) ≥ t > (127.0 mm) t > (203.2 mm)

PREHEAT - °C (None*) (21°C) (66°C) (107°C) (149°C) (177°C)

*When the base metal temperature is below 32 °F (0 °C), the base metal shall be preheated to at least 70 °F (21 °C), and this minimum temperature maintained during welding. TABLE 8.2.1 8.2.2

Preheat shall be checked using temperature indicating crayons, pyrometers, or other suitable devices.

______________________________________________________________________________ WELDING, SPEC. NO. A06-000009 REV 7 FABRICATION, PAGE: 10 of 18 AND INSPECTION APPROVED BY: VS REQUIREMENTS ISSUE DATE: 10 March 2004 MILL SHELLS SUPERSEDE DATE: 11 Oct 2000 8.3

WELDING PROCEDURES All welding procedures to be used shall be prepared by the manufacturer, contractor, or fabricator as written weld procedure specifications (WPS) and procedure qualification records (PQR), and shall be available to those authorized to review them. Submittal of procedures may be required.

8.3.1

PREQUALIFIED WELDING PROCEDURES All prequalified joint welding procedures to be used shall be prepared by the manufacturer, contractor, or fabricator as written weld procedure specifications (WPS), and shall be available to those authorized to examine them. Submittal of procedures may be required.

8.3.2

WELDING PROCEDURES REQUIRING QUALIFICATION

8.3.2.1

Welding procedures not conforming to the requirements of prequalified procedures, shall comply with the following: a.

Welding procedures shall be qualified prior to use by tests as prescribed in AWS D1.1, Section 5, Part B.

b.

Welding procedures shall be submitted as written procedure qualification records (PQR) and weld procedure specifications (WPS).

c.

Welding procedures require the approval of Division Engineering/Quality Assurance before being used in fabrication.

8.3.2.2

At the discretion of Division Engineering/Quality Assurance, evidence of previous qualification of the joint welding procedures to be used, or qualifications of welders, welding operators, and tackers may be accepted.

8.4

GROOVE WELD BACKING and RUN-OFF TABS

8.4.1

Extension bars, starting and run-off tabs, backing bars, etc. used during welding of the base metals, as defined by paragraph 6.1 of this specification, shall be of equivalent material.

8.4.2

Backing bars, spacers, tabs, etc. shall be completely removed.

9.0

STRESS RELIEF (HEAT TREATMENT)

9.1

Stress relief shall be performed after all welding has been completed, but before final machining.

______________________________________________________________________________ WELDING, SPEC. NO. A06-000009 REV 7 FABRICATION, PAGE: 11 of 18 AND INSPECTION APPROVED BY: VS REQUIREMENTS ISSUE DATE: 10 March 2004 MILL SHELLS SUPERSEDE DATE: 11 Oct 2000

EXAMPLE POSITIONS FOR MILL SHELLS DURING STRESS RELIEF * PREFERRED POSITION:

B R A C IN G L O C A T IO N

S ID E V IE W *

FLO O R

BRACING LOCATION

FLOOR

FLOOR END VIEW

SUPPORT UNDER BRACING

SIDE VIEW

BRACING LEG MUST BE PERPENDICULAR TO SUPPORTS UNDER SHELL

FIGURE 9.2

______________________________________________________________________________ WELDING, SPEC. NO. A06-000009 REV 7 FABRICATION, PAGE: 12 of 18 AND INSPECTION APPROVED BY: VS REQUIREMENTS ISSUE DATE: 10 March 2004 MILL SHELLS SUPERSEDE DATE: 11 Oct 2000 9.2

It shall be the responsibility of the manufacturer to ensure dimensional stability during stress relief by use of additional temporary bracing, stiffeners, or other adequate means. All bracing or temporary attachments shall be properly vented. Drawings and procedures shall be submitted to Division Engineering/Quality Assurance for review. (See Figure 9.2)

9.3

Stress relief shall conform to the following requirements.

9.3.1

The temperature of the furnace shall not exceed 600 °F (315 °C) at the time the weld assembly is to be placed inside.

9.3.2

Above 600 °F (315 °C), the rate of heating shall be no more than 400 °F (220 °C) per hour divided by the maximum metal thickness of the thickest part in inches*, but in no case more than 400 °F (220 °C) per hour. During the heating period, variation in temperature throughout the part being heated shall be no greater than 250 °F (140 °C) within any 15 feet (4.6 m) interval of length. *The rates of heating and cooling need not be less than 100 °F (55 °C) per hour. However, in all cases, consideration of closed chambers and complex structures may indicate reduced rates of heating and cooling to avoid structural damage due to excessive thermal gradients.

9.3.3

After a mean temperature range between 1100-1200 °F (590-650 °C) is reached, the temperature of the part shall be held within this range for a time not less than that specified in Table 9.3.3, based on the thickness of the thickest weld. During the holding period, there shall not be a difference greater than 150 °F (84 °C) between the highest and lowest temperature throughout the part being heated. Hold time shall start when the lowest thermocouple reading reaches 1100 °F (590 °C). t ≤ 1/4 inch t ≤ (6.4 mm) 15 minutes

2 inches ≥ t > 1/4 inch (50.8 mm) ≥ t > (6.4 mm) 1 hour/inch (25.4 mm)

t > 2 inches t > (50.8 mm) 2 hours + 15 minutes for each additional inch (25.4 mm) over 2 inches (50.8 mm)

NOTE: t = thickness of weld TABLE 9.3.3 9.3.4

Above 600 °F (315 °C), cooling shall be done in a closed furnace or cooling chamber at a rate no greater than 500 °F (278 °C) per hour divided by the maximum metal thickness of the thickest part in inches*, but in no case more than 500 °F (278 °C) per hour. From 600 °F (315 °C) the assembly may be cooled in still air. *The rates of heating and cooling need not be less than 100 °F (55 °C) per hour. However, in all cases, consideration of closed chambers and complex structures may indicate reduced rates of heating and cooling to avoid structural damage due to excessive thermal gradients.

______________________________________________________________________________ WELDING, SPEC. NO. A06-000009 REV 7 FABRICATION, PAGE: 13 of 18 AND INSPECTION APPROVED BY: VS REQUIREMENTS ISSUE DATE: 10 March 2004 MILL SHELLS SUPERSEDE DATE: 11 Oct 2000 9.3.5

A minimum of four (4) thermocouples shall be attached to each piece being stress relieved, and temperature charts shall be maintained and submitted to Division Engineering/Quality Assurance. One thermocouple shall be attached to the thinnest section and one to the thickest section of the piece. The number of thermocouples may be reduced with the approval of Division Engineering/Quality Assurance.

10.0

INSPECTION a.

A report shall be submitted for each nondestructive testing (NDT) inspection performed, including repairs.

b.

Additional testing may be required by Quality Assurance, if weld repairs are excessive.

10.1

MATERIALS INSPECTION

10.1.1

Prior to acceptance for use in fabrication, all plate shall be visually (VT) inspected in the following manner:

10.1.2

a.

No laminar discontinuities shall be permitted. Repair or rejection of plate shall be decided by Division Engineering/Quality Assurance prior to any weld repair.

b.

If approved for repair by Division Engineering/Quality Assurance, laminar discontinuities shall be gouged out and the affected area shall be weld repaired. Laminar discontinuities too large to be economically weld repaired shall be repaired by cutting out the affected area and welding a section of sound plate in its place.

c.

Weld repair procedures shall be in accordance with the requirements of this specification.

d.

Repair welds shall have the same quality requirements as finished welds. Testing shall be performed immediately following repairs.

Prior to acceptance for use in fabrication, all plate shall be ultrasonically (UT) inspected in the following manner: a.

Inspection shall be in accordance with ASTM A578 - Standard Specification for Straight-Beam Ultrasonic Examination of Plain and Clad Steel Plates for Special Applications.

b.

9-inch grid of plate surface shall be tested.

c.

Acceptance criteria shall be ASTM A578 Level B, as follows:

______________________________________________________________________________ WELDING, SPEC. NO. A06-000009 REV 7 FABRICATION, PAGE: 14 of 18 AND INSPECTION APPROVED BY: VS REQUIREMENTS ISSUE DATE: 10 March 2004 MILL SHELLS SUPERSEDE DATE: 11 Oct 2000 Any area where one or more discontinuities produce a continuous total loss of back reflection accompanied by continuous indications on the same plane that cannot be encompassed within a circle whose diameter is 3 inches (75 mm), or 1/2 of the plate thickness, whichever is greater, is unacceptable. In addition, two or more discontinuities smaller than described above shall be unacceptable unless separated by a minimum distance equal to the greatest diameter of the larger discontinuity or unless they may be collectively encompassed by the circle described above. 10.2

INSPECTION OF FLAME CUT OR MACHINED EDGES PREPARED FOR WELDING

10.2.1

Visual (VT) inspection shall be performed on all edges prepared for welding as follows:

10.2.2

a.

Visual (VT) inspection for linear indications shall be in accordance with paragraph 10.1.1 of this specification.

b.

In addition notches shall be repaired in accordance with AWS D1.1 paragraph 5.15.

Ultrasonic (UT) inspection shall be performed on all steel plate in accordance with ASTM A578 and in the following manner: a.

100% of plate within 2 lineal inches (50 mm) of prepared edges or within twice the thickness of the plate, whichever is greater.

b.

100% of all flange material.

c.

Acceptance criteria shall be as follows: i.

Cylinder Plates A. ASTM A578 Level B, as follows: Any area where one or more discontinuities produce a continuous total loss of back reflection accompanied by continuous indications on the same plane that cannot be encompassed within a circle whose diameter is 3 inches (75 mm), or 1/2 of the plate thickness, whichever is greater, is unacceptable. In addition, two or more discontinuities smaller than described above shall be unacceptable unless separated by a minimum distance equal to the greatest diameter of the larger discontinuity or unless they may be collectively encompassed by the circle described above.

______________________________________________________________________________ WELDING, SPEC. NO. A06-000009 REV 7 FABRICATION, PAGE: 15 of 18 AND INSPECTION APPROVED BY: VS REQUIREMENTS ISSUE DATE: 10 March 2004 MILL SHELLS SUPERSEDE DATE: 11 Oct 2000 ii. Flange Material, Cone Plates and Trunnion Ring Bolting Material A. All discontinuities causing complete loss of back reflection are unacceptable. B. For material 1½ inches and thicker, all indications with amplitudes equal to or greater than 50% of the initial back reflection and accompanied by a 50% loss of back reflection that cannot be encompassed within a 3 inch (75 mm) diameter circle are unacceptable. d.

If approved by Division Engineering, plate may be repaired in accordance with this specification.

10.3

ADDITIONAL INSPECTION OF CONTOURED FLANGES

10.3.1.1

Magnetic particle (MT) inspection, using dry method, after rough machining shall be performed as follows: a.

All weld prep areas.

b.

Contour radius side of flange that does not receive additional machining.

10.3.2

Magnetic particle (MT) inspection, using dry or wet method, after final machining shall be performed on all machined surfaces.

10.3.3

Acceptance criteria for magnetic particle (MT) inspection of contoured flanges shall be as follows: a.

No linear indications larger than 1/8 inch (3.2 mm).

b.

No rounded indications larger than 1/8 inch (3.2 mm).

10.4

WELD INSPECTION

10.4.1

WELD INSPECTION CRITERIA FOR VT, MT, AND UT Any rejectable areas after stress relief must be reviewed by Division Engineering/Quality Assurance on an individual case basis to determine approved procedures for repair and repeat of stress relief. No procedure using air arc or welding will be permitted after stress relief without a repeat of stress relief.

10.4.1.1

VISUAL (VT) INSPECTION CRITERIA - ALL WELDS Acceptance criteria shall be as follows: a.

The weld has no cracks.

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10.4.1.2

10.4.1.3

b.

Thorough fusion exists between adjacent layers of weld metal and between weld metal and base metal.

c.

All craters are filled to the full cross-section of the weld.

d.

Weld profiles shall be in accordance with AWS D1.1, Section 5.24 and paragraph 7.4 of this specification.

e.

The frequency of piping porosity in fillet welds shall not exceed one (1) instance in each 4 inches (100 mm) of length, and the maximum diameter shall not exceed 3/32 inch (2 mm).

f.

A fillet weld in any single continuous weld shall be permitted to underrun the nominal fillet weld size required by 1/16 inch (1.6 mm) without correction, provided that the undersize portion of the weld does not exceed 10 percent (10%) of the length of the weld.

g.

Complete joint penetration groove welds in butt joints transverse to the direction of computed tensile stress shall have no piping porosity. For all other groove welds, the frequency of piping porosity shall not exceed one (1) instance in each 4 inches (100 mm) of length, and the maximum diameter shall not exceed 3/32 inch (2 mm).

h.

Undercut shall be no more than 0.01 inch (0.25 mm) deep if the weld is transverse to the primary stress direction in the part that is undercut. Undercut shall be no more than 1/32 inch (1 mm) deep if the weld is parallel to the primary stress direction in the part that is undercut.

i.

All welds designated per the drawing shall be contoured by grinding to provide a gradual and smooth transition between base metal and weld metal. Grinding shall be performed in accordance with paragraph 7.4 of this specification.

MAGNETIC PARTICLE (MT) INSPECTION CRITERIA - ALL WELDS a.

Magnetic particle inspection shall be performed in accordance with ASTM E709 Standard Guide for Magnetic Particle Examination.

b.

Acceptance criteria shall be to AWS D1.1 statically loaded in table 6.1 for all welds.

ULTRASONIC (UT) INSPECTION CRITERIA - FULL PENETRATION WELDS a.

Ultrasonic inspection shall be performed in accordance with AWS D1.1, Section 6, Part F.

b.

Acceptance criteria shall be to AWS D1.1, table 6.2, for all welds.

______________________________________________________________________________ WELDING, SPEC. NO. A06-000009 REV 7 FABRICATION, PAGE: 17 of 18 AND INSPECTION APPROVED BY: VS REQUIREMENTS ISSUE DATE: 10 March 2004 MILL SHELLS SUPERSEDE DATE: 11 Oct 2000 c.

All weld reinforcements shall be ground smooth, so that proper coupling is achieved between the ground surface and the transducer.

d.

All full penetration welds shall be scanned with 45°, 60°, and 70° angles at 20 dB over reference level when single leg (Leg 1) is used, otherwise AWS D1.1 must be followed.

e.

Additional inspection for full penetration tee and corner welds shall be as follows: i.

Ultrasonic inspection shall be performed from the surface opposite the weld for a distance equal to twice the weld thickness. (See Sketch 10.4.1.3)

t 2t

Tr ans duc er

SKETCH 10.4.1.3

ii. The method used shall be as described by ASTM A435 - Standard Specification for Straight-Beam Ultrasonic Examination of Steel Plates. iii. Material separation or lamellar tears shall be rejected. f.

All full penetration welds shall be tested for transverse cracks.

g.

Additional procedures may be required by Division Engineering/Quality Assurance due to joint configuration.

10.4.2

EXTENT OF WELD INSPECTION

10.4.2.1

UPON COMPLETION OF ALL WELDS OR PRIOR TO STRESS RELIEF a.

Visual (VT) Inspection: All welds shall be visually inspected 100% over their entire length.

b.

Magnetic Particle (MT) Inspection: All welds shall be magnetic particle inspected 100% over their entire length.

c.

Ultrasonic (UT) Inspection: All full penetration welds shall be ultrasonically inspected 100% over their entire length.

______________________________________________________________________________ WELDING, SPEC. NO. A06-000009 REV 7 FABRICATION, PAGE: 18 of 18 AND INSPECTION APPROVED BY: VS REQUIREMENTS ISSUE DATE: 10 March 2004 MILL SHELLS SUPERSEDE DATE: 11 Oct 2000 10.4.2.2

AFTER STRESS RELIEF a.

Magnetic Particle (MT) Inspection: All welds shall be magnetic particle inspected 100% over their entire length.

b.

Ultrasonic (UT) Inspection: Full penetration welds shall be ultrasonically inspected 10%. When testing reveals rejectable indications, 100% of the entire weld joint shall be tested.

10.4.2.3

After stress relief, any rejectable areas must be reviewed by Division Engineering/ Quality Assurance on an individual case basis to determine approved procedures for repair and repeat of stress relief. No procedure using air arc or welding will be permitted after stress relief without a repeat of stress relief.

10.5

OTHER REQUIREMENTS FOR INSPECTION

10.5.1

Any additional inspection to be performed shall be described on detail drawings or in special addendums to this specification.

10.5.2

Additional testing, as mentioned in paragraph 10.0 of this specification, shall be addressed in writing.

11.0

QA DOCUMENTATION TO BE SUBMITTED The following documents are to be submitted when the following inspections or processes are to be performed (per this specification).

11.1

MATERIAL CERTIFICATIONS: [including ultrasonic (UT) inspection reports of raw materials, if performed at the mill.]

11.2

NONDESTRUCTIVE TEST (NDT) REPORTS

11.2.1

MAGNETIC PARTICLE (MT) INSPECTION

11.2.2

a.

Reports for plate prepared for welding

b.

Reports for welds before and after stress relief

ULTRASONIC (UT) INSPECTION a.

Reports for plate prepared for welding

b.

Reports for welds before and after stress relief

11.3

HEAT TREATMENT RECORDS

11.4

RECORD OF DIMENSIONAL INSPECTION