Ordering 1018 cold drawn steel... would you specify astm #? 1

[USAeng]

First off, I am a fairly new engineer and the only engineer at my company - so sorry about the newbie question.

Say you want to machine something out of cold drawn steel bar grade 1018 or whatever grade.

Would you specify A29 AND A108 on the purchase order? Maybe just one of the other.... or would you just order 1018 cold drawn bar?

Another question: This is for a component being made per asme B31.1. I do not see anything in B31.1 that shows A29 or A108 bar as an acceptable material, but I think their material listing is for specs normally used in power piping. Would bar stock be up to the engineer to determine its acceptablily for use? or is there any references in the piping code that someone knows about?

Thank you.

 

[metengr]

USAeng;
Here are answers to your two questions;

1. Yes, when ordering material you should reference a material specification or standard, like ASTM, AMS or ASME, when possible. The reason is that you know what your purchasing. Using trade names or numbers for materials should be avoided.

2. ASME B31.1 does allow for use of non-listed materials in Appendix A. The pitfall for this approach is that you need to verify allowable stresses for pressure-retaining applications, and these allowable stresses must be the same or more conservative than those found in Appendix A.

 

[SnTMan]

USAeng, you should only order by a specification number when you care about what the supplier sends you.

I am not familiar with B31.1, but the typical ASME code approach is that unless a material is permitted, it is prohibited.

Regards,

Mike

 

[USAeng]

So would you order the bar using both the more general A29 spec and the A108 spec or only one or the other for some reason? The A29 spec has the chemistry info for 1018 but the A108 is specific for cold drawn bar. Thank you very much.

 

[metengr]

Use the A 108 specification, the A 29 specification is referenced in A 108.

 

[USAeng]

Thank you very much!

 

[vthomidis]

.....yes you'd better order uing A108 this being a more precise spec.

In general when inquiring or ordering material to suppliers it is advisable to use as accurate spec. as possible ( or as available ).

On the other hand, be sure that in any case they will offer or propose what they have available and the choices are usually not very wide.

From the hundreds of different grades,conditions etc. specified in the various codes, only quite a few are actually available in the market.