Fastener manufacturers will encounter the problem of hydrogen embrittlement in the process of producing fasteners. The brittle fracture caused by hydrogen embrittlement generally occurs suddenly and unpredictably, and the consequences caused by this failure form are very serious. Therefore, it is necessary to reduce the generation of hydrogen embrittlement. The removal of hydrogen embrittlement of electroplated fasteners is a very important surface treatment.

1. Causes and hazards of hydrogen embrittlement of rivet nut fasteners Due to the reaction of cathodic protection or corrosion, It is possible for hydrogen atom to enter the matrix of steel or other metals and stay in the matrix. Under the stress state lower than the yield strength (nominal strength of alloy), it may lead to the reduction or loss of extensibility or bearing capacity, cracks (usually submicroscopic), and even sudden fracture during service or storage, resulting in serious brittle failure. There are many reasons for hydrogen embrittlement of fasteners, but electroplating process is one of the key factors. The brittle fracture of fasteners due to hydrogen embrittlement generally occurs suddenly and unpredictably, so the consequences of this failure form are very serious. Especially when there are safety requirements, it is necessary to reduce the generation of hydrogen embrittlement. Therefore, it is very important to remove hydrogen embrittlement from electroplated fasteners.

Riveting nut

2. The situation and characteristics of the risk of hydrogen embrittlement failure of rivet nut fasteners

A. High tensile strength or hardening or surface hardening;

B. Adsorbed hydrogen atom;

C. Under tensile stress. With the increase of part hardness, carbon content and cold work hardening degree, during pickling and electroplating. The solubility of hydrogen and therefore the total amount of hydrogen generated and absorbed will also increase, which means that the hydrogen embrittlement sensitivity of parts will be stronger. Parts with smaller diameters are more sensitive to hydrogen embrittlement than parts with larger diameters.