Exam 1: Corrosion and Materials

Permanent deformation occurring at relatively low stress levels as a result of localized overheating is called ________.

____________ is a form of environmental cracking that can initiate on the surface of high strength low alloy steels and carbon steels with highly localized zones of high hardness in the weld metal and HAZ as a result of exposure to aqueous HF acid service.

Which of these materials are susceptible to creep damage?

In pressure containing equipment, SOHIC and SCC damage is most often associated with __________.

High temperature hydrogen attack results from exposure to hydrogen at elevated temperatures and pressures. The hydrogen reacts with __________ in steel to produce _________, which cannot diffuse through the steel. The loss of carbides causes an overall loss in strength.

The severity of hydrochloric acid corrosion ________ with _________ HCl concentration and increasing temperatures.

In susceptible materials, the primary factor that affects sigma phase formation is the ________ at elevated temperatures.

Amine stress corrosion cracking is most often associated with lean amine services. The pure alkanolamine does not cause cracking. Cracking in rich amine services are most often associated with _______ problems.

Corrosion due to acidic sour water containing H₂S at a pH between 4.5 and 7.0 is called sour water corrosion. Carbon dioxide (CO₂) may also be present. Which of the following materials is susceptible to sour water corrosion?

What is the chemical symbol for ethane or ethylene?

With ammonia stress corrosion cracking weld hardness should not exceed _______ BHN.

A carbon steel bundle from the overhead condenser in the crude unit operates at 300º F and is in hydrochloric acid service. It showed severe pitting type corrosion when pulled for inspection. What type of material would be best suited for this service?

Which of the following materials are generally not suitable for HF service?

________ eliminates the susceptibility of most common steels to SCC.

________ significantly increases the probability and severity of blistering, HIC and SOHIC damage.

Dissimilar weld metal cracking can be aggravated by _______.

High strength steels are susceptible to LME when they come in contact with molten ________.

_________ is the main concern during start-up, shutdown and/or hydro testing for equipment/piping operating at elevated temperatures. This event can also occur in an auto refrigeration event in units processing light hydrocarbons.

Which material does not have an endurance limit?

Wet H₂S services or _________ acid services are process where hydrogen diffuses into the steel and hydrogen embrittlement (HE) is an issue.