Weldability of ASTM A148 2

[MechEng1977]

I am wondering how well ASTM A148 - (105-85) Cast Steel can be welded to a CSA 50W plate?

We are currently welding a ASTM A27 Cast Steel to a 50W plate but would like to upgrade the material.

Thanks in advance.

 

[metengr]

The A 148 Grade 105-85 is weldable with suitable precautions for preheat and possible post weld heat treatment.

 

[arunmrao]

ASTM 148 is a high strength steel casting of weldable grade. However,certain precautions need to be taken before welding.Please refer to the specs. The carbon and Manganese in ASTM 148 are about 0.28% and 1.2% respectively.

 

[MechEng1977]

Thanks for the responses, I have a few more questions. Yes, sadly I am working Today:

1) Within ASTM A148: between the different grades, is
90-60 more weldable than 105-85?

2) ASTM A148 does not provide a chemical composition, "Arunmaro" where did you get those values.

3)I came across an interesting formuale for weldability from the ASM Metals Handbook 2nd Ed:

CE = %C + %Mn/6 + %Ni/15 + %Cu/15 + %Cr/5 + %Mo/5 + %V/5

When CE < 0.45%, weld cracking is unlikely and no heat treatment is required


Has anybody used this formuale with confidence. If so, how can you apply it to ASTM A148

Thanks in advance

 

[arunmrao]

90-60 is more weldable than 105-85. I got the values, as I make those grades of castings. I intentionally gave you the values as the standard does not specify chemistry or heat treatment,it only specifies the mechanical properties. The foundry and casting user together decide the chemistry.

 

[metengr]

Yes, typically as the carbon content is lowered because of lower strength requirements the weldability of the steel increases, where preheat and other measures to prevent cracking are less likely.

The carbon equivalent (CE) equation is used to evaluate "weldability" of steel (cast or wrought), where besides carbon content, other alloying elements as arunmrao mentioned are considered. However, to successfully apply the CE equation you need to know the chemical composition of the steels you are joining.

 

[MechEng1977]

How much less weldable is 105-85 compared to 90-60?
Can you quantify it, maybe with carbon content of either?

 

[arunmrao]

With 105-85,you need to add Ni and Mo,some add copper too.Carbon about 0.3-0.32% max and Manganese levels 1.2-1.4% max. The heat treatment cycle varies in each of the 2 cases.

 

[MechEng1977]

Compared to ASTM A27 - 70-36, can you compare weldability.
I noticed the Manganese is less for A27, does that mean it welds better or easier?

 

[metengr]

MechEng1977;
ASTM A 27 is a specification for carbon steel castings for general application. Because of their lower strength, fewer precautions are required for welding, in comparison to higher strength grades, and they are less sensitive to cracking during or after welding.

 

[MechEng1977]

Assuming all precautions for welding are taken (electrode, heat treat), and the weld is performed properly is the ASTM A148 - 90-60 more robust when compared to ASTM A27 - 70-36?

Or is the 90-60 still more likely to crack in service. I just want to make sure the switch to the higher grade material will be worth the change.

Thanks

 

[metengr]

MechEng1977;
Given your statement above,

Assuming all precautions for welding are taken (electrode, heat treat), and the weld is performed properly is the ASTM A148 - 90-60 more robust when compared to ASTM A27 - 70-36?

....


The switch to the higher strength casting only provides more margin for strength, nothing else. The issue of cracking susceptibility does not factor in given the statement above.

 

[MechEng1977]

Ok, so taking the engineering approach, I calculated the CE:

ASTM A27 70/36 CE = 0.47

ASTM A148

90/60 CE = 0.48 (Assume no Ni, Cu, and Mo) (C=0.28, Mn=1.2)

105/85 CE > 0.48 (There is Ni, Cu, and Mo how much???)

As for Grade 80/50, and 80/40 do you know the approx chemical comp???


If the above is correct, the 90/60 is as weldable as the 70-36. The 105/85 is not as weldable by a factor of x

 

[MechEng1977]

The tumbleweed blows across the quiet desert landscape, with nothing in its path it faces a quiet isolation but hopefuly it will find a Material Science Expert to once again help its cause? Hahah Thanks for listening