AWS D8.1M:2013 pdf download.Specification for Automotive Weld Quality - Resistance Spot Welding of Steel
1.1 Scope. This specification defines quality characteristics and metrics pertinent to resistance spot welds on steels used in automotive applications. The evaluation methods and inspection criteria specified herein can be used to evaluate the effec-tiveness of particular welding equipment and procedures used to weld a particular base material combination. The criteria and metrics are the same for all welds regardless of the service load. The quality standards established by this specification do not constitute a lower bound of suitability for service; welds that do not meet the weld quality criteria of this specifica-tion may be satisfactory for certain applications. The acceptance criteria of this standard are not intended for applications outside this scope (such as post-crash weld quality assessment): attempts to do so may lead to an erroneous result.
4. Weld Process Control
Production-welded parts being joined by the resistance spot welding process have inherent variability of weld quality characteristics. Therefore, some tolerance must be established for the required quality so as to be consistent with the manufacturing process capabilities. The welding process must be controlled to meet or exceed the minimum weld qual-ity level meeting the product requirements. Information and guidance pertaining to supplier requirements for process and product control are contained in the Quality System Requirements, QS-9000 Third Edition, or in the latest edition of ISO/TS 16949， Quality Systems 一Automotive suppliers 一Particular requirements for the application of ISO 9001:2000, published by the Automotive Industry Action Group (AIAG).
5. Spot Weld Acceptance Criteria
The intended use of this specification is to satisfy the needs of both shop floor and laboratory applications to define auto-motive weld quality. Not all inspection methods of this specification need to be applied simultaneously to determine weld quality. Rather, the test method(s) most appropriate for the application, as determined by an agreement between the customer and supplier, shall be considered adequate to define the weld quality for a specific application.
5.3.1 Weld Size. In destructive testing, weld size is determined by measuring the known fused area.In most instances this means measuring only button and partial thickness fractures (i.e., material protruding from one of the previously welded sheets). Interfacial fractures can be included in the measurement only when proven to be part of a nugget by other means such as metallographic inspection.
The weld size is calculated as the average of the maximum dimension and the minimum dimension, which may not always be 90° from each other. These measurements are typically made with calipers. Irregular shaped welds are mea-sured as shown in Figures 8 and 9. All welds must not exceed an aspect ratio of 2 to 1. A tail might be formed on a button by destructively tearing the two sheets apart shall not be included in the button measurement.AWS D8.1M pdf download.