On 2018-08-08 14:48:54
Surface treatment of well type heat treatment furnace mold
Heat treatment of prehardened steel plastic mold
1. Pre-hard steel is supplied in the pre-hard state. Generally, heat treatment is not required, but sometimes it is necessary to change forging.
2. Spheroidization annealing is usually adopted in the pre-heat treatment of prehardened steel to eliminate the forging stress, obtain the uniform spherical pearlite structure, reduce the hardness, improve the plasticity, and improve the cutting performance or cold extrusion forming performance of the die blank.
3. The pre-hardening process of pre-hardening steel in well heat treatment furnace is simple, most of which adopts tempering and tempering treatment, and the tempered sostenite structure is obtained after tempering and tempering. High temperature tempering temperature range is very wide to meet the mold of various working hardness requirements. Due to the good hardenability of this kind of steel, quenching can be used oil cooling, air cooling or nitrate classification quenching.
Heat treatment of aging hardened steel plastic mold
1. The heat treatment process of aging hardened steel is divided into two basic steps. Firstly, solid solution treatment is carried out, that is, the steel is heated to a high temperature, and various alloy elements are dissolved into austenite. After the austenite is finished, martensite structure is obtained by quenching. The second step is to carry out aging treatment and use aging strengthening to reach the final mechanical properties.
2. Solid solution treatment heating is generally carried out in the salt bath furnace and box-type furnace. The heating time is respectively 1min/mm and 2 ~ 2.5min/mm. If the final forging temperature can be accurately controlled during forging, the solid solution quenching can be carried out directly after forging.
3. Aging treatment is best carried out in a vacuum furnace. If it is carried out in a box-type furnace, in order to prevent the surface oxidation of mold cavity, the furnace must be filled with a protective atmosphere, or aluminum oxide powder, graphite powder and cast iron scrap should be used for aging under the condition of packing and protection. The heat preservation time should be extended properly, otherwise it is difficult to reach the aging effect.
Surface treatment of plastic mold
In order to improve the wear and corrosion resistance of the surface of the plastic mold, it is often appropriate surface treatment.
1. Plastic mold chrome plating is a most used surface treatment method, chrome plating layer in the atmosphere has a strong passivation ability, can keep metal luster for a long time, in a variety of acidic media are not chemical reactions. The coating hardness is up to 1000HV, so it has excellent wear resistance. Chromium plating layer also has a high heat resistance, heating in the air to 500℃ when its appearance and hardness is still not significantly changed.
2. Nitriding has the advantages of low treatment temperature (generally 550 ~ 570℃), little deformation of the mold and high hardness of the infiltration layer (up to 1000 ~ 1200HV), so it is also very suitable for surface treatment of plastic mold. Steel containing chromium, molybdenum, aluminum, vanadium and titanium has better nitriding performance than carbon steel. Suitable surface treatment methods for plastic mold include: nitrocarburizing, electroless nickel plating, ion plating of titanium nitride, titanium carbide or titanium nitride, deposition of hard film or super hard film by PVD, CVD, etc. In order to improve the wear and corrosion resistance of the surface of the plastic mold, it is often appropriate surface treatment. Plastic die chromium plating is one of the most used surface treatment methods, chromium plating layer in the atmosphere has a strong passivation ability, can keep the metal luster for a long time, in a variety of acidic media are not chemical reactions. The coating hardness is up to 1000HV, so it has excellent wear resistance. Chromium plating layer also has a high heat resistance, heating in the air to 500℃ when its appearance and hardness is still not significantly changed.