ASTM International - ASTM B839-04
Standard Test Method for Residual Embrittlement in Metallic Coated, Externally Threaded Articles, Fasteners, and Rod—Inclined Wedge Method
|Publication Date:||1 April 2004|
|ICS Code (Fasteners in general):||21.060.01|
significance And Use:
The use of this test method can significantly reduce the risk of sudden catastrophic failure of threaded articles and fasteners, below their design strength, due to hydrogen embrittlement.
1.1 This test method covers the determination of, on a statistical basis, the probability of the existence of hydrogen embrittlement or degradation in:
1.1.1 A batch of barrel electroplated, autocatalytic plated, phosphated, or chemically processed threaded articles or fasteners and
1.1.2 A batch of rack plated threaded articles, fasteners, or rod.
1.2 Industrial practice for threaded articles, fasteners, and rod has evolved three graduated levels of test exposure to ensure reduced risk of hydrogen embrittlement (see Section 3). These levels have evolved from commercial applications having varying levels of criticality. In essence, they represent the confidence level that is required. They also represent the time that finished goods are held before they can be shipped and used. This time equates to additional cost to the manufacturer that may of necessity be added to the cost of the finished goods.
1.3 This test method is applicable to threaded articles, fasteners, and rod made from steel with ≥1000 MPa (with corresponding hardness values of 300 HV10 kgf, 303 HB, or 31 HRc) or surface hardened threaded articles, fasteners, or rod.
1.4 This test method shall be carried out after hydrogen embrittlement relief heat treatment in accordance with the requirements of Guide B 850. It may also be used for assessing differences in processing solutions, conditions, and techniques. This test method has two main functions: first, when used with a statistical sampling plan it can be used for lot acceptance or rejection, and second, it can be used as a control test to determine the effectiveness of the various processing steps including pre- and post-baking treatments to reduce the mobile hydrogen in the articles, fasteners, or rod. While this test method is capable of indicating those items that are embrittled to the extent defined in Section 3, it does not guarantee complete freedom from embrittlement.
1.5 This test method does not relieve the processor from imposing and monitoring suitable process control.
1.6 This test method has been coordinated with ISO/DIS 10587 and is technically equivalent. (Warning-Great care should be taken when applying this test method. The heads of embrittled articles, fasteners, or rod may suddenly break off and become flying projectiles capable of causing blindness or other serious injury. This hazard can occur as long as 200 h after the test has started. Hence, shields or other apparatus should be provided to avoid such injury.)
Note 1-The use of inhibitors in acid pickling baths does not necessarily guarantee avoidance of hydrogen embrittlement.
1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.