QC/T 29087-2023Permissible welding variation in dimensions without tolerance indication
1 Scope
This document specifies the permissible welding variation in dimensions without tolerance indication in automobile parts affected by the welding process.
This document is applicable to the permissible welding variation in dimensions and angles without tolerance indication in automobile sheet metal parts and profiles formed through welding.
This document is not applicable to the welding dimension and weld dimension checked according to the main model.
2 Normative references
The following documents contain requirements which, through reference in this text, constitute provisions of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 1800.1 Geometrical product specifications (GPS) - ISO code system for tolerances on linear sizes - Part 1: Basis of tolerances, deviations and fits
GB/T 3375 Welding terminology
GB/T 19804 Welding - General tolerances for welded constructions - Dimensions for lengths and angles - Shape and position
QC/T 266 Automobile parts - Limit deviation of dimensions without tolerance indicated - General requirements
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 1800.1, GB/T 3375, GB/T 19804, QC/T 266 and the following apply.
3.1
flanging
forming method with vertical edge on inner hole or outer edge of workpiece under the action of a mold
3.2
trim
boundary of a part obtained by cutting off the excess edge of the part by a mold or an equipment
4 Permissible welding variation in dimensions without tolerance indication in automobile sheet metal welding process
There are two main forms of lap joints for automobile sheet metal, i.e., flush lap joint (as shown in Figure 1) and flanged lap joint (as shown in Figure 2), wherein, the former has less impact on welding than the latter.
Figure 1 Flush lap joint Figure 2 Flanged lap joint
As shown in Figure 3, the two parts are welded through hole positioning respectively, and the flanging height a, one of the measured features, is less than or equal to 150mm. In the figure, l1 is the permissible welding variation in dimensions without tolerance indication between the trim and the flanged surface (or trim) after welding; I2 is the permissible welding variation in dimensions without tolerance indication between the positioning hole and the flanged surface (or trim) after welding; l3 is the permissible welding variation in dimensions without tolerance indication between the flanged surface and the flanged surface after welding; l4 is the permissible welding variation in dimensions without tolerance indication between the positioning hole and the trim after welding.
Figure 3 Schematic cross-section of the relative relationship between the characteristics of two lap forms
Two parts are welded in the same procedure. Considering the basic dimensions of the parts, their own tolerance fluctuations and the effect brought by the welding process, the permissible welding variation in dimensions without tolerance indication for the measured features in Figure 3 is shown in Table 1.
Contents
Foreword III
1 Scope
2 Normative references
3 Terms and definitions
4 Permissible welding variation in dimensions without tolerance indication in automobile sheet metal welding process
5 Permissible welding variation in dimensions without tolerance indication for welded nuts and studs
6 Permissible welding variation in dimensions without tolerance indication for gas shielded welding
7 Permissible welding variation in dimensions without tolerance indication for profile welding structure
8 Indications on drawings for permissible welding variation in dimensions without tolerance indication
