New Trial Paper BGas

BGAS-CSWIP TRIAL EXAM PAPER NAME DATE

: :

PLEASE ANSWER ALL QUESTION. 1-

What is a Corrosion? Degradation of metal by chemical or electro-chemical.

2-

Name the three factor needed for corrosion to occour. Anodes ( positively charge ), Cathodes ( negatively charge ) and Electrolyte.

3-

Name three factors which can accelerate corrosion reaction. Temprature, Hygroscopic salts, bacteria, acids and alkalies, bi-metallic contact and aerobic conditions.

4-

What is a Millscale, when and where does it occour? The Oxides of iron form in blue colour with varies thickness from 25µm to 100µm. These Oxides are compressed at very high temprature during rolling mill operation and appear on top of the substrate.

5-

What is the Duplex Process in surface preparation? Pickling process followed by a passivation process using Phosphoric or Chromic acids.

6-

What is a " Deadman Handle " ? Safety devices as a blasting nozzle triggers which must always under operator direction.

7-

What function does a primer have in a paint system? Wet out the substrate and provides excellent adhesion and also provide key for any subsequence layer and passivate the substrate.

8-

Give the main differences between Airless and Conventional spray units. Production rate is higher when using Airless spray unit and a paint thickness can achieves in one layer compare to Conventional spray unit.

9-

What is a mean of BGC PS PA9? Properties and performance of paint,which covered in Bgas Specification.

10-

What is the reaso this Additives added in a paint formula? a)- Anti setteling agent b)-Plasticiser For a shelf life and stop Gives a paint flexibelity and reduces brittlenes settelment. c)-Driers d)-Anti skinning For oxidising an oil and To retrad the formation of a skin on the surface of resins a paint.

11-

What is defination of Viscosity? A fluid resistance to flow.

12-

What is meant by high viscosity? A fluid with a high resistance to flow, paint will not run easily.

13-

What information could be obtained from this accelerated test box. a)-Humidity Cabinet b)-Salt Spray Cabinets Test for Tropical condition Test for salts laden envitonment c)-Water Soak Test Test for water absorption

d)-Temprature Cycling test for constant temprature cycle from hot to cold

14-

What is meant by CPVC? Critical Pigment Volume Concentration

15-

Please describe, the causes and how to remedy, a)- Blistering b)-Ropiness

16-

c) Cissing

d)-Flocculation

e)-Lifting

f)-Cratering