ASTM A333 GRADE 6 Q&T WITH HIGH YIELD AND TENSILE STRENGTH FOR SOUR SERVICE 1

[chrysa1975]

We have procured ASTM A333 GRADE 6 for sour service and there are two points that need clarification.

1. in the material requisition there is a requirement for yield strength and ultimate tensile strength not to exceed the specified minimum value by more than 20,000 psi. However the MTC depict higher YS and UTS than specified.

2. pipes are Quenched & Tempered, instead of Normalized as required for Sour Service.

The questions are:

1. who can the yield strength and tensile strength reach such high values, and if it affects the behavior of the pipe in the sour service.

2. is there a possibility Quenched and tempered to be accepted, for example an additional heat treatment or testing?

Thank you in advance

 

[weldstan]

The material does not meet the purchase requiremens. Reject it. The strength and hardness is the result of the the carbon equivalent and tempering temp. after quenching.

 

[EdStainless]

The wrong HT and the wrong properties, sounds like you need a different supplier.

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P.E. Metallurgy, consulting work welcomed

 

[chrysa1975]

Thank you both! Indeed materials shall be rejected. However, please also note the following.
1. The Ceq is 0.42 and the maximum hardness stated in the MTC is 188HV10. The tempering temperature is 630degC+10. I still cannot understand the high YS and TS values.
2. Quench and tempering is not a listed heat treatment in ISO 15156-2 A.2.1. How the mill states that material ASTM A333 GRADE 6 quenched and tempered is per NACE for SOUR service?
3. Is there a maximum value of YS and TS for ASTM A333 GRADE 6?

Thanks in advance

 

[EdStainless]

3. No, as long as the min elongation is met it meets the basic spec.

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P.E. Metallurgy, consulting work welcomed

 

[SJones]

2. Quenched and tempered is a listed heat treatment in ISO 15156-2 - A.2.1.2, item f). It is also an allowable heat treatment condition for Grade 6

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/in/drstevejones

All answers are personal opinions only and are in no way connected with any employer.

 

[chrysa1975]

Thank you both!
@SJones, in ISO 15156-2 A.2.1.2 f) the heat treatment includes as a first step austenitizing. But our material is ASTM A333 6 Q&T. How do we escape this step? How can I support it to the client? Thanks in advance!

 

[SJones]

@chrysa
You have materials against your name. Look up heat treatment in your metallurgy books. Quenching occurs from the austenitising temperature, it's just that nobody, except the ISO crew, uses "austenitising, quenching, and tempering" as a descriptor

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/in/drstevejones

All answers are personal opinions only and are in no way connected with any employer.

 

[EdStainless]

For example the AMS (aerospace) specs just call it Q&T, but the first step is austenitize.
There is a temperature for that and a minimum temperature for entering the quench.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

 

[chrysa1975]

Really thanks weldstan, Edstainless and SJones!!!! Your help is valuable!!!
FYI, I am just sharing with you that the materials have been accepted, claiming that SSCC is a reduced risk due to the hardness value in the base material which is 188 HV10 and the operating temperature which is above 100 degrees Celsius.

 

[SJones]

Another success for Eng-Tips

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/in/drstevejones

All answers are personal opinions only and are in no way connected with any employer.