AISI/SAE 1020 as a substitute for A36

[Carburize]

I need a large block 9-inch thick welded to an A36 assembly by fillet welding. Typically heavy section A 36 plate is also used for this piece but I cannot get the material I need within the delivery schedule, I can however get AISI 1020 meeting A36 mechanical properties.
Are there any downsides to substituting the 1020?

 

[metengr]

Carburize;
If you have an MTR on the AISI Type 1020, I would run a quick CE to compare with the chemical composition requirements for the thickness listed in Table 2 of ASTM A 36. If the CE's and mechanicals are similar, I see no problems with your approach.

 

[Carburize]

CE of the plate offered is 0.29 - everything complies with A36 apart from low manganese. Mechanical properties are all within A36 specifciation limits for the plate thickness.

 

[metengr]

How low is the Mn? There is a note in Table 2 that mentions a specific range of Mn (0.85-1.20%) and Si (0.15-0.40%) for shapes that are over 465 Lbs/ft.

Does your job require strict adherence to ASTM material standards?

 

[metengr]

Correction to Mn range 0.85-1.35% and 426 lbs/ft for shapes.

 

[Carburize]

Manganese is 0.5% - no the job does not need strict compliance with an ASTM material standard - I can specify whatever I want, I havet ypically used the A36 because it has been reasonably readily available.

 

[metengr]

For fillet welding, I see no real problems with using the AISI Type 1020 steel plate. The higher Mn would have more of an effect regarding hardenability to achieve the minimum mechanical properties (which you have met), and combining with sulfur to reduce hot-shortness during forming operations.

 

[Carburize]

The material is actually very clean 0.007% Sulfur - I am going to use it.

Thanks for your input