On 2018-08-08 14:48:54
What are the methods of surface heat treatment
Metal heat treatment, surface heat treatment is only heating the surface of the workpiece to change its mechanical function of the surface metal heat treatment technology. In order to heat only the surface layer of the workpiece without too much heat entering into the workpiece, the heat source used must have a high energy density, that is, to give a larger heat energy to the workpiece per unit area, so that the surface layer or part of the workpiece can reach a high temperature in a short time or instantaneously. The methods of surface heat treatment include flame quenching and induction heating heat treatment. The commonly used heat sources are flame such as oxyacetylene or oxypropane, induction current, laser and electron beam.
The development of heat treatment is accompanied by the development of mechanical manufacturing industry. Mechanical manufacturing puts forward higher requirements for heat treatment, and the heat treatment of mold is a high-tech part of heat treatment. As we all know, die heat treatment is to develop the potential of die material and improve the performance of die. The performance of the die must meet the following requirements: high strength (including high temperature strength, cold and hot fatigue resistance), high hardness (wear resistance) and high toughness, as well as good machinability (including good polishing), weldability and corrosion resistance.
The typical steel is 1Cr18Ni9Ti. Main heat treatment methods: 1) solid solution. When the casting is heated to 950-1175 ℃, the process of low temperature preheating first and then rapid heating to solution temperature should be adopted. 2) Solution + stabilization. After solution treatment, the castings containing titanium and niobium should be stabilized. That is to say, reheat the casting to 850-930 ℃, and then quickly cool it. To prevent chromium carbide precipitation and improve the resistance to grain boundary corrosion. In order to make the metal parts have the required mechanical, physical and chemical properties, in addition to the reasonable selection of materials and various forming processes, heat treatment process is often essential.
Steel is a widely used material in mechanical industry. The microstructure of steel is complex and can be controlled by heat treatment, so the heat treatment of steel is the main content of metal heat treatment. In order to make the metal parts have the required mechanical, physical and chemical properties, in addition to the reasonable selection of materials and various forming processes, heat treatment process is often essential. Steel is a widely used material in mechanical industry. The microstructure of steel is complex and can be controlled by heat treatment, so the heat treatment of steel is the main content of metal heat treatment.
In addition, aluminum, copper, magnesium, titanium and their alloys can also change their mechanical, physical and chemical properties through heat treatment, so as to obtain different service properties. Metal heat treatment is to heat the metal workpiece in a certain medium to a suitable temperature, and maintain the temperature for a certain time, and then heat treatment furnace at different speeds Degree cooling, a process of controlling the properties of a metal material by changing its surface or internal structure.