Patent ID: 6107595
Filing Date: 2000-08-22
Classification: B23K

Abstract:
A welded steel product in which two steel members are resistance welded together at a weld location on said product, said product comprising:first and second steel members each in the form of a flat steel strip and each having a first portion thereof at said weld location;each first portion being in superimposed relation to the first portion of the other steel member, said superimposed portions defining an area of mutual overlap for said steel members;a filler sandwiched between said superimposed first portions of the first and second steel members at said weld location;a resistance weldment, at said weld location, fusing the first and second steel members together at their respective first portions and fusing said filler to each steel member;said weldment being substantially devoid of solidification cracking extensive enough to produce an unacceptable weld fracture;said first and second steel members each having respective steel compositions which are ferritic and non-stainless and which, when said members are resistance welded solely to each other, can produce solidification cracking in said weldment extensive enough to produce an unacceptable weld fracture;at least one of said steel compositions comprising a combination of elements at least one of which has a concentration which contributes substantially to said solidification cracking;said filler having a composition which differs from the compositions of said steel members and which, at said weld location, modifies the weldment composition otherwise due solely to said first and second steel members, to reduce substantially said solidification cracking and provide a weldment which produces an acceptable weld fracture;said filler composition comprising means for diluting, in said weldment, the concentration of at least said one element in said steel composition, to reduce substantially the contribution of that element to solidification cracking;said filler having one of the following combinations of features, (a) or (b):(a) said filler being in the form of an insert, said insert being composed of essentially pure iron or interstitial-free steel and having a thickness which is substantially greater than 5% of the total thickness of said two steel members and said insert, said insert being relatively flat, and all of said insert which is sandwiched between said superimposed first portions of the steel members occupying less than said area of overlap defined by said superimposed portions;(b) said filler being in the form of a metallized layer cohered to the surface of one of said steel members at said weld location, and composed of essentially pure iron, and having a thickness greater than 5% of the total thickness of said two steel members and said metallized layer.