Heating is only one of the processes in metal heat treatment process, but if there is no reasonable heating in the heating process, there will be a series of defects, and even the metal material can not be used normally. Hebei Yuantuo Mechanical and Electrical Factory shares some common problems in metal heat treatment and heating.
1. Overheat phenomenon
During the heat treatment, the heat is most likely to lead to the coarsening of the austenite grains, and the mechanical properties of the parts can be reduced. It is generally considered that the impurities such as MnS are dissolved in the austenite and enriched in the crystal interface because the heating temperature is too high, and the inclusions are precipitated along the crystal interface at the time of cooling, and are easy to break along the grain boundary of the coarse austenite at the time of the impact.
2. Over-burning phenomenon
The heating temperature is too high, which not only causes the austenite grain to be coarse, but also the grain boundary is locally oxidized or melted, leading to the weakening of the grain boundary, which is called overburning. The performance of the steel after over-burning is seriously deteriorated, and cracks are formed in the quenching process. The overfired tissue cannot be recovered and can only be scrapped. So that the occurrence of overburning is avoided in the work.
3. Decarburization and oxidation
when the steel is heated, the carbon in the surface layer reacts with oxygen, hydrogen, carbon dioxide and water vapor in the medium (or atmosphere), so that the surface hardness, the fatigue strength and the wear resistance of the surface layer carbon concentration are reduced, And the surface-forming residual tensile stress is easy to form surface mesh cracks.
4. Hydrogen embrittlement is called hydrogen embrittlement
when high strength steel is heated in hydrogen rich atmosphere. Hydrogen embrittlement can also be eliminated by hydrogen removal treatment (such as tempering, aging, etc.). Hydrogen embrittlement can be avoided by vacuum, low hydrogen atmosphere or inertia atmosphere heating.
Overseas manager: Tom Wang
Phone: 0086-13303078975(whatsapp, wechat,line)
Specialist of induction heat treatment furnace in China; Glad to be your business partner in induction heating field.
Post time: 11-27-2019