Material Specification

[STEVEBR]

Can anyone recommend a steel with the following properties:

1) Must be available in solid billet form up to approx 175mm to allow deep hole boring operation to take place.
2) Material must be weldable, preferrably using the MIG / MAG or TIG processes.
3) Must be heat treatable to achieve a Rp0.2 > 680N/mm².

Thanks

 

[CoryPad]

How much of the 175 mm diameter is left after hole boring? If the final diameter after machining and before heat treatment is most of the original 175 mm, then you need a deep hardening steel, say 4340. If the final wall thickness after machining is much smaller, than a lower alloy steel like 4140 could suffice.

Regards,

Cory

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[metengr]

STEVEBR;
Your laundry list of needs is too general for selection of a suitable material. You need to further itemize this list by application of the component in service; reviewing service temperature ranges, corrosion environment concerns, and additional minimum mechanical properties (ultimate tensile, yield strength and ductility). Also, is the component being used in an application that requires high reliability or exposure to personnel safety?

Fabrication welding needs to be carefully considered because it is highly probable that post weld heat treatment or even re-heat treatment after fabrication will be necessary to assure minimum mechanical properties. High stregnth low alloy steels demand careful attention during welding fabrication.

So, take a moment and itemize your list to cover as much information as possible.

 

[TVP]

If you can heat treat after the welding, then there are any number of grades that could be specified. In general when weldability is a concern you want to the carbon content to be below ~ 0.20% by mass. However, hardenability is a concern if you want to achieve a yield strength of 680 MPa minimum. After the deep hole boring what will be the nominal wall thickness? A grade like SAE 10B21 can easily be heat treated to 680 MPa yield strength, but only for a section thickness of ~ 10 mm. Anything more than that requires greater hardenability, which can be provided by alloying elements like Cr, Mo, etc. which are not as detrimental to weldability.

 

[STEVEBR]

Hi

Thanks for your reply's. Here is the additional information as requested:

1) Wall thickness after deep hole bore 10 - 25mm
2) Base thickness up to 45mm
3) No concerns over service temperature ranges
4) Corrosion resistance - Components are plated, specification dependant on location & application.
5) Ultimate value - No design calculations are based on UTS
6) % Elongation >10%
7) For welding purposes a material with a CEV value <0.6 would be required

We currently use a material - Grade 600:BS 6258, 0.22%C, 1.5% Mn 0.08 - 0.12% V) which is readily weldable after Q&T to achieve Re >750 N/mm2. My only problem with this material is that it only comes in cylinder form and not billet.

Thanks for your assistance

 

[TVP]

Steve,

That grade would be called 15V22 according to ASTM A 29 or 19MnVS6 according to EN 100267. Neither of these would be laying on the shelf of a steel service center/stockist, but they are certainly produced in large diameter bars. I am sure that Corus can/does produce this.

 

[CoryPad]

How are you differentiating between a cylinder form and a billet?

Regards,

Cory

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[STEVEBR]

Hi Cory

Billet is in solid bar form, cylinder allready has a bore

regards

Steve