Exam 1: Corrosion and Materials

Which of the following materials are susceptible to polythionic acid SCC?

If wet electrodes or high moisture content flux weld electrodes are used to weld carbon steel, hydrogen can be charged into the steel resulting in _________.

Carbonate stress corrosion cracking usually occurs at welds or cold worked areas that __________.

SCC tendency ________ towards the alkaline pH region

The level of creep damage is a function of the material and the coincident _________ level at which the creep deformation occurs.

With CUI, corrosion rates __________ with increasing metal temperatures up to the point where the water evaporates quickly.

Low alloy steels contain a maximum of _______ chrome.

Corrosion under insulation is more severe between ________ and ____________.

Corrosion rates of the anode will be less affected if there is a _________ anode to cathode ratio.

Sulfidation is primarily caused by ________ and other reactive sulfur species as a result of the thermal decomposition of sulfur compounds at high temperatures.

Thermal fatigue damage is in the form of cracking that may occur anywhere in a metallic component where relative movement is constrained, particularly under repeated __________.

Cracks associated with brittle fracture will typically be _________.

Which of these materials are susceptible to brittle fracture?

In HF service, carbon steel operating above ________ should be closely monitored for loss in thickness and may need to be upgraded to Alloy 400.

Ammonium chloride corrosion is the general or localized corrosion, often pitting, normally occurring under ammonium chloride or amine salt deposits. All commonly used materials are susceptible to ammonium chloride corrosion. A small amount of _________ can lead to very aggressive corrosion.

Hydrogen blisters may form as surface bulges on the ID, the OD on within the wall thickness of a pipe or pressure vessel. Blistering occurs from hydrogen generated by ______, not hydrogen gas from the process stream.

Thermal fatigue cracks propagate ________ to the stress and are usually dagger shaped, transgranular and oxide-filled.

The removal of surface material by impacting materials is called:

Carbonate cracking typically propagates _________ to the weld; the pattern of cracking observed on the surface is sometimes described as ________.

Stress ruptures are characterized by _________ failures and are usually accompanied by thinning at the fracture surface.