Seam welding

摘要

A process is provided for scam welding advanced high strength steel sheets together. Respective end portions of first and second advanced high strength steel sheets are placed in overlapping contact with one another, and subjected to first and second weld passes. In the first weld pass, a seam welder including weld electrodes operate at a first-pass applied current and a first-pass pressure and are moved relative to the overlapping end portions at a first-pass carriage speed to establish a weld seam containing a weld nugget with a martensite phase. In the second weld pass, the weld electrodes operate at a second-pass applied current and a second-pass pressure and move relative to the weld seam at a second-pass carriage speed selected to fuse microcracks, lap openings, and porosity in the seam, relieve the residual stress in the joint, and temper the martensite phase of the weld nugget, and thereby form a weld joint.

主权项

1. A process for seam welding advanced high strength steel sheets together, comprising:
placing respective end portions of first and second advanced high strength steel sheets in overlapping contact with one another to provide overlapping end portions with opposite first and second sides; subjecting the overlapping end portions to a first weld pass of a seam welder comprising weld electrodes operating at a first-pass applied current and a first-pass pressure and being moved relative to the overlapping end portions from the first side to the second side of the overlapping end portions at a first-pass carriage speed to pass electric current through the overlapping end portions and establish a weld seam comprising a weld nugget comprising a martensite phase; and subsequent to the first weld pass, starting at either the first side or the second side of the overlapping end portions and subjecting the weld seam to a second weld pass of the seam welder in which the weld electrodes operate at a second-pass applied current that is lower than the first-pass applied current and at a second-pass pressure and move relative to the weld seam at a second-pass carriage speed selected to pass electric current through the overlapping end portions and fuse microcracks, lap openings, and porosity in the weld seam, relieve the residual stress in the weld seam, and temper the martensite phase of the weld nugget, and thereby forming a weld joint.