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The CORRECT CHOICE is (d) Warren TEST, Streicher test and huey test

The explanation is: Warren test, Streicher test and huey test are the CORROSION testing’s for stainless steel. The primary function of these testing’s is to find out the sensitized stainless-steel metal SPECIMENS.

Right answer is (b) Mils per year (MPY)

To explain I WOULD SAY: Mils per year is commonly used corrosion rate expression as it MEASURES corrosion rate in terms of depth of penetration of pit. Whereas milligram sq. decimeter per day (MDD) measures the corrosion rate in terms of WEIGHT loss of metal.

The correct answer is (C) 0.46 MPY

To explain I would say: Corrosion PENETRATION rate = K (ai/nD)

a = atomic weight of IRON = 55.8 g

i = current density = 1 micrometer/sq. Centimeters

n = valency CHANGE = 2

D = density of iron = 7.86 g/cm^3

K = 0.129 for steel

Corrosion penetration rate = 0.129 * [(55.8) / (2*7.86)] = 0.46 mpy.

Correct CHOICE is (d) Temperature, DISSOLVED oxygen, and nature of metal

To elaborate: The factors that AFFECT CORROSION testing are:

i. Temperature

ii. Dissolved oxygen

iii. Nature of metal

iv. The concentration of the corrosive solution

v. Specifications of the specimen (FABRICATION history, metallurgical history).

Correct answer is (B) False

Explanation: Polymeric materials CORRODE differently RATHER than processes associated with metallic corrosion. Metallic corrosion results in the electrochemical REACTIONS with the dissolution of metal into metal ions. Whereas polymers result in physicochemical processes.

Right option is (a) Copper and its alloys

To elaborate: Temperature is one of the IMPORTANT factors of corrosion. In many cases, an increase in temperature INCREASES the corrosion rate of METALS. Whereas it decreases in copper alloys due to the removal of dissolved OXYGEN.

Right choice is (b) Pilot-plant testing

For explanation I WOULD say: Pilot-plant tests are USUALLY best and more desirable. It duplicates the intended large-scale OPERATION environment by using the same raw materials, CONCENTRATIONS, temperature, and volume of corrosive solution to the area of METAL exposed.

The CORRECT ANSWER is (b) A rapid and ready conversion table for various corrosion rate units

Best explanation: Nomography for corrosion rate is a table in which it READILY converts one corrosion rate UNIT into another corrosion another unit. Units of corrosion rate are namely MILS per year (MPY), milligram sq. Decimeter per day (MDD).

The correct answer is (a) True

For explanation: A surface finish of a specimen is ONE of the factors of corrosion. It is necessary to have a standard surface CONDITION to facilitate comparison with another result. A common and widely used surface finish is produced by polishing with 120 numbered ABRASIVE cloth.

Correct choice is (C) To evaluate PAINTED surfaces and electroplated parts

The EXPLANATION is: Salt-spray test is a type of CORROSION TESTING in which specimen is exposed to seawater or salt water in a box. It is usually used to evaluate painted surfaces and electroplated parts.

The correct ANSWER is (d) Laboratory, pilot-PLANT and field testing

To elaborate: Types of CORROSION testings:

Laboratory testing

Pilot-plant testing

Actual plant service TEST

Field test.

The correct choice is (b) MILS per year = 534W/DAT

To EXPLAIN: Standard expression to measure the corrosion rate in mils per year = 534W/DAT.

Where D is the density of metal, W is weight loss in milligrams, A is the AREA of exposure in sq. inches, T is TIME in hours.

The CORRECT option is (a) True

For explanation I WOULD say: Polymers are the large and heavy molecular chains FORMED from the interaction of many monomeric UNITS. It includes plastics, elastomers, and materials like POLYSTYRENE, etc.

Right ANSWER is (B) REPORTING maximum depth of a pit

The best explanation: Pitting corrosion is one of the types of corrosion in which PERFORATED metal is formed DUE to the formation of holes on the metal surface. The best way to report the corrosion testing of pitting is to report the maximum depth of a pit.

Correct ANSWER is (d) The appearance of coating, presence, and extent of corrosion and under FILM corrosion

Explanation: The FACTORS that are considered to EVALUATE the PAINT test are:

i. Appearance of coating

ii. Presence and extent of corrosion

iii. Under film corrosion.

The correct answer is (d) POLISHING belts, emery papers, and electrolytic polishing

For explanation I would say: The surface FINISH of the specimen is one of the FACTORS of CORROSION. Surface preparation of a specimen can be done by using polishing belts, emery papers, and electrolytic polishing.

The correct option is (d) SANDBLASTING, rubber-stopper and use of CHEMICAL and SOLVENTS

The best explanation: Cleaning methods after the EXPOSURE of specimen:

Mechanical methods such as scraping, brushing, sandblasting and the rubber stopper

Chemical methods in which chemical solutions and solvents are used for removal

Electrolytic methods in which specimen is made cathode under an impressed current.

Right answer is (d) Evaluation and selection of materials for a specific ENVIRONMENT, to know the effect on the corrosion of metals by addition of inhibitors and to study the MECHANISM of corrosion

The best explanation: PURPOSE of corrosion TESTING are:

Evaluation and selection of materials for a specific environment

To know the effect of corrosion on metals by the addition of inhibitors

To study the mechanism of corrosion

To CONTROL the corrosion resistance of metal or corrosiveness of the environment.

Right ANSWER is (b) Corrosion penetration RATE = K (ai/nD)

The explanation: The corrosion rate EXPRESSION that is used for electrochemical techniques to determine corrosion penetration rate is K (ai/nD) where a is the atomic weight of the metal, i is current density (in microamperes per sq. centimeters), n is the number of electrons lost, D is the density of metal, K is CONSTANT depends on the penetration rate desired.

The CORRECT choice is (d) Swelling, dissolution and bond rupture

For explanation: The physicochemical PROCESSES that occur in POLYMERS DUE to the corrosive ENVIRONMENT are:

Swelling

Dissolution

Bond rupture.

Right choice is (d) COPPER and its alloys, cast iron and steels

To elaborate: DISSOLVED oxygen will be reduced cathodically into hydroxide ions in many of the corrosion systems and it INCREASES the dissolution of metal anodically. METALS such as copper and its alloys, cast iron and steels are subjected to INCREASE attack in the presence of oxygen.

The correct option is (B) CORROSION at the interface of liquid and gases in a pipeline or tank

Best explanation: Liquid-line corrosion is a special TYPE of corrosion that occurs at the interface of liquid and GAS in a pipeline or tank. It occurs due to the availability of water vapor and OXYGEN at the interface along with impurities.

Right choice is (d) BOILING 65% nitric acid is used as a corrosive SOLUTION and used to evaluate the heat treatment of stainless steels

For explanation I would say: The HUEY test is used to check the heat treatment of stainless steels. It USES boiling 65% nitric acid as a corrosive solution. Stainless steel is an alloy of iron, carbon, chromium, and nickel.

Correct CHOICE is (a) True

For explanation: Corrodibility of the metal is defined as the capability of being CORRODED. It may decrease or increase during the corrosion test as a function of TIME. It increases as it OWING to the formation of a protective layer or it decreases as it owing removal of the more resistant surface layer.

Right option is (B) Schematic arrangement of corrosion DATA with the change in TEMPERATURE and CONCENTRATION

Easy explanation: Nelson’s method is a method of summarizing data of corrosion in which the corrosion rate of particular metal is reported with a change in temperature and concentration of the corrosive SOLUTION.

The correct answer is (d) CHEMICAL composition, fabrication HISTORY, and metallurgical history

Easiest EXPLANATION: Exact chemical composition, fabrication history, and metallurgical history of a specimen are must increase the reliability of a corrosion test. Specimen with 1/16 to ¼ inch THICK, 1 inch WIDE, and 2-inch-long are commonly employed for laboratory testing.