We have a structural weldment that is to be welded, AWS D1.1 2004 is the applicable welding code.
This involves qualification to section 4 with one of the base metals being unlisted.
There is a plate (A-36) with a piece of 4140 round bar that needs to be attached by a fillet weld.
Specifics about weld process have not been decided yet, and prbably not needed to asnswer this type of question.
I cannot see where condition of the plate before welding (hot rolled, annealed ect.) might be mentioned as a variable.
If I purchase the 4140 as hot rolled can the WPS be written for both hot rolled and annealed plate ?

Thanks in advance.

The condition of the base metal is a very important factor in producing a successful weld. Post weld heat treatment is always considered to be an essential variable by welding standards. However, most welding standards do not seem to consider the initial state of heat treatment when qualifying the welding procedure specification.

AWS D1.1 operates on the assumption that the materials of construction are weldable steel that have a history of successful use. That is one condition of prequalification. If the designer/engineer selects a base metal without a proven history of successful use, i.e., weldability, a condition of prequalification is not met. It is then up to the user to demonstrate the proposed welding procedure will produce acceptable results.

Welding standards define the minimum requirements that must be met by the manufacturer when designing, fabricating, and inspecting weldments. They also specify the minimum requirements that must be met when qualifying welding procedures and welders. Welding standards are typically developed with certain base metal types in mind. For example AWS D1.1 is intended for steels typical used in the construction of steel framed buildings. Steels not typically used for steel construction, i.e., those having yield strength of more than 100 ksi for example, are not listed as prequalified. If the user intends to utilize the materials not listed by the welding standard, the user takes on the added responsibility of investigating the use of the unlisted material. The presumption is that the user is knowledgeable about welding and factors that influence the probability of success. With that in mind, the "welding engineer" is presumed to know what factors must be considered during the design and fabrication phases of the project. Conditions that are beyond the scope of the minimum requirements invoked when qualifying the welding procedure specification must be carefully weighed by the "welding engineer." Those factors, such as the state of heat treatment, must be considered and factored into the selection of base metals and welding parameters used in production. A good example would be the weldability of PH stainless steels. An attempt to weld a PH stainless steel in the quenched and precipitation hardened condition is likely to be met with unsatisfactory results. The highest probability for success will occur when the PH stainless steel is welded in the annealed condition. This is where training and experience of the welding engineer comes to bear.

If the manufacturer is welding a base metal that is heat treatable, it is assumed the individual tasked with materials selection is knowledgeable and recognizes the state of heat treatment of the purchased material it is an important consideration. The qualified WPS should limit the state of heat treatment to those conditions that allow for successful welding. It makes little sense to use annealed plate while welding the test coupon and then permit the use of hardened material for fabrication. While the applicable welding standard may not address this issue, it is presumed that the user understands the principles of heat treatment and the character of the base metals selected for construction. Ultimately it is the manufacturer's responsibility to ensure the products produced are safe and function as intended. Failure to do so has been the root cause of financial ruin for more than a few companies.

Case in point, has anyone noticed "Smiling Bob" seems to be absent from the television lately. Evidently the product didn't produce the results advertised. ;)

Best regards - Al