Rolled bar in Forging ASTM certificate (ASTM A182)

[Stdsp]

ASTM A 182, which is for forging, permits cylindrical rolled bar, that are 4" and lower in diameter, provided the bar is heat treated, to be certified as ASTM A 182.
A) How and where can we get the basis / rationale behind this permission?
B) Some people advocate that asking for forged cylindrical bar especially small diameter such as 4" and lowers (so long as it is solution annealed, in case of Austenitic stainless steel and meets the mechanical and chemical property) is an overkill, and actually non-sense requirement, since, in the process of making a rolled bar of such small diameter, the work that goes into that eliminates the need for forging process. Is this argument valid?
C) It is my submission that some user prefers forged bar for high fatigue items due to fear of presence of defects and due to fear of micro segregation, and strength along the grain flow will be higher, could this be rationale for one asking for forged bar instead of rolled bar.
D) In a cylindrical rolled cylindrical bar if one does macro section and checks for the grain flow and a forged bar of same size one does the macro section, forged bar and rolled bar will have same kind of macro result on grain flow, is this correct statement?
E) Since the diameter being low, the threat of segregation and threat of presence of injurious defects are reduced to such an extent in a rolled bar (of 4" and lower) that there is no technical difference between forged bar and rolled bar when the size is 4" and less especially when the shape is cylindrical and final required shape is also cylindrical. May (D) and (E) be the rationale behind ASTM A 182 allowing rolled bar to be certified under ASTM that is dedicated for forging?

 

[metengr]

Very simply, send an inquiry into the ASTM committee for this material specification or better yet attend ASTM meetings and become an active member, like some of the code committee volunteers that frequent these forums. You can complain till the cows come home or take action by actively attending meetings.

 

[EdStainless]

If you look around you will find companies that have added their own additional requirements.
Such as roll bar permitted, provided that the reduction ratio is greater than XX.
I believe reduction ratio is what is at the root of this.
When the spec was written no one was thin strand casting these alloys so 4" bar was being rolled from 10" or 12" at least.
But what if today someone rolled it from 5"? That is a different animal.

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Plymouth Tube

 

[Stdsp]

Dear metengr

Is there a contact mail ID for ASTM committee?
Does it change from one ASTM to another?

 

[EdStainless]

You can go to ASTM.org and find out which committee is responsible for A182, and who the Chairman is.
You can sen him a letter through ASTM headquarters.

But honestly, I suggest that you join. Dues are cheap and you will learn a lot by sitting through the meetings and talking with the other members.

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Plymouth Tube

 

[tbuelna]

The spec has requirements for grain properties. 4" round bar is right around the limit of what can be produced with cold rolling versus hot rolling. I imagine the intent of the spec is to preclude using a hot rolled bar machined to a smaller diameter, where the grain properties at the core may not be adequate.

It is also common to control the diameter or cross section of bar stock used for forging blanks, since the grain properties of the blank can affect the grain properties in the forging.

 

[Cleandive]

Not all alloys in A 182 requires grain property

 

[weldstan]

As per EdStainless, it is based on hot work reduction and may well need amending. Today's steel making produces comntinuous cast bar with subsequent hot working. It has not been uncommon to find bar stock, including reforging bar/billets that do not have the appropriate hot work. Forged flanges have leaked because the reforging billet did not have adequate hot work.

 

[OGMetEngr]

Simply stated, if you need certain properties at the center of the bar you should perform mechanical / corrosion / etc. testing at the center of the bar. Regardless of whether it is rolled, rotary forged, press forged, hammer forged, the material properties should be tested where the properties are needed. If you find that rolled bar does not meet your needs, it should be written into the procurement specification that rolled bar is not allowed (regardless of what A182 states).

 

[Stdsp]

For comodity like Valve bodies (take the case of 2" Check valve or ball valve), where the material (for the body adaptor or body) is hollow (center is bored out), use of rolled bar should be fine with the above logic. Assume the mechanical properties are verified towards the outside diameter, then it should be fine since the center of the end component is going to be hollow, if on the other hand the property in the center is OK, then the property at the outside diameter should also be OK.

 

[tbuelna]

A conventionally rolled round bar may not have the same grain properties as a round forged bar. Conventionally rolled bar should have a grain flow that is predominantly longitudinal, but it is possible for a piece of round stock that was roll forged from a larger diameter disc of material to end up with a grain flow that is more circumferential due to the rolling direction.