Valve Magazine


Last updateThu, 17 Apr 2014 1pm

Back You are here: Home Magazine Sections Materials Q&A

Materials Q&A

Do I need to be concerned about galvanic corrosion when selecting valve materials?

materials q and a 300x300A: This is a good question, and the answer should begin with discussing exactly what is meant by galvanic corrosion.

Have PMI testing limitations changed with the advances in technology?

materials q and a 300x300A: The short answer is that the situation has changed in some ways, but that PMI still has limitations. The long answer is a bit more complicated. First, let’s clarify what is meant by the term PMI (which stands for positive material identification).

Titanium Valve Grades

materials q and a 300x300Q: Why are cast titanium valves commonly offered in grades different than my wrought pipe?


Nickel-Copper Alloys

materials_q_and_a_graphicQ: Are the nickel-copper alloys (such as UNS N04400) acceptable for use in accordance with the NACE sour service standards?

NACE MR0103 Material Compliance

materials_q_and_a_graphicQ: I have a material certified to be compliant with NACE MR0175. Is that material also compliant with NACE MR0103?

Which Valve for Nitric Acid Service?

materials_q_and_a_graphicQ: I requested CF8 valves but the supplier is offering CF8M valves at less cost. However, I am not sure this alternative is a good choice for my nitric acid service. Are my concerns warranted?


Addressing Welding Procedures Not Covered by ASME Section IX

materials_q_and_a_graphicQ: My customer has rejected my welding procedure specification (WPS) and has asked me to address items that are not required by ASME Section IX. Is this reasonable?

HIC Testing

materials_q_and_a_graphicQ: I’m working on an order in which the customer’s material specification imposes HIC testing. What is HIC testing?

Cobalt-base Alloy 6

materials_q_and_a_graphicQ: Is there a problem using cobalt-base Alloy 6 material in amine applications in refineries and gas treatment plants?

Cast or Forged?

materials_q_and_a_graphicQ: Should I be concerned whether my valve is cast or forged?



materials_q_and_a_graphicQ: In the last Materials Q&A column, you discussed using forged bar to make hubbed-flange components such as bonnets. I noticed that ASTM A182 specifically states that forged bar cannot be used for flanges. Was your original statement in error?

Sponsored Products


Valve Magazine Digital Edition

SPR14 CVR 160x214Inside the Spring 2014 issue…

• Tank Cars
• Shale Gas
• New Globe Standard