GMW17354

Description / Abstract: Material Description. This standard defines the requirements for laser welded coils used by GM or GM suppliers in the manufacture of stamped sheet steel parts in progressive die processes. It applies only to the assupplied condition of tailored coils.

Symbols. Not applicable.

Applicability. Typical applications for these coils include typical progressive die parts benefitting from multigauge construction including, but are not limited to, structural cross members and longitudinal rails. In certain instances and when the business case is justified, tailored coils may be used for coil fed blanking/transfer press processes.

Remarks. Coils supplied under this standard shall be made by laser butt welding two or more hot or rolled, coated or uncoated steel coils used for subsequent progressive die or coil fed blanking/transfer press forming.

For the requirements of the component steel coils, the relevant GMW specifications apply. This specification is applicable only to steels with a tensile strength of 980 MPa maximum, but specific grade/gauge component coil combinations shall be reviewed by the tailor welded coil supplier to determine capability.

For coated blanks all requirements shall be fulfilled for hot dipped or electrogalvanized zinc coatings according to GMW8 and GMW11, respectively.

In a tailor welded coil, the coil will wind according to thicker gauge. Coil stability and prevention from tipping must be considered. In a single-welded coil, the thicker gauge shall make up a minimum of 40% of the width on a fullsized coil. Single weld coils with a thicker gauge not exceeding 40% of the width or multi-weld coils shall be reviewed by the tailor welded coil supplier to determine feasibility to ensure adequate coil balance prior to shipment to any GM or GM supplier facility. Coil design/part changes or coil size restrictions may be required to ensure adequate coil balance and to prevent tipping.