Solution for Plastic Mold heat treatment Issue
Plastic mold making failure mostly factors of heat treatment of this important aspect of. Because of the above heat treatment of general failure caused by improper accounting for about 50% of total failure mould. In order to give full play to the potential properties of mould steel, mould machining should be conducted after the quenching, tempering heat treatment in heat treatment, heating temperature, holding time, the length of the cooling speed of process parameter selection is not appropriate will be die failure factors. A machined good plastic mould,if lost due to improper heat treatment and its use value, is in the economy and the loss of time is very big, must adopt various measures to prevent mouth
Carbon and alloy elements with more influence of die steel of heating rate, poor thermal conductivity. So in the heat treatment (especially the quenching) heating speed not too fast, should be more slowly, to prevent mold deformation and cracking. Heating in air furnace quenching, in order to prevent oxidation and decarburization, using packing to protect heating, this heating speed is not fast, but the diathermy also slower, so won’t produce big thermal stress, relatively safe. In the use of salt bath furnace processing, mold heating speed fast, diathermy is also very fast, die inside and outside by thermal stress, if not properly controlled, it is easy to cause deformation or crack, resulting in failure of die, must be used to prevent or slow heating preheating acceleration
Plastic mold making will normally need heat treatment if you want the mold running over 1 million of life time shots
Die quenching effect of oxidation and decarburization is at very high temperatures, if not strictly controlled atmosphere, it is prone to oxidation and decarburization on the surface. But most die quenching, tempering after removal in local work surface grinding, the rest nearly no processing, therefore, oxidation and decarburization in heat treatment will also make the mold cause early failure. When the oxidation, mold surface easy to scratch, size, easy to produce fatigue crack in early use, when caused by decarburization, surface hardness significantly reduced resulting in early wear.
In addition, decarburization mould surface after due to differences in inner and outer layer of tissue, cooling appear larger tissue stress often leads to quenching crack. In order to prevent oxidation and decarburization of mold can be used to protect the processing, packing box, filling materials filling anti oxidation and decarburization, sealed after heating. In addition, also can use salt bath furnace, controlled atmosphere furnace, vacuum furnace. Adopting the controlled atmosphere furnace must be strict control of carbon potential level of carbon potential is too low, will cause the same plastic mold surface decarburization, but carbon potential also cannot be too high, otherwise, although not happen decarburization, but often lead to make the surface of steel carburization embrittlement, which significantly reduce the fatigue strength of steel
Die casting manufacturer has the same issue during die casting mold making/
The quenching temperature effect of quenching temperature significantly influence the performance of various mold. The quenching temperature is too high, easy to grow up, and make a lot of carbide dissolution of the matrix, the formation of coarse needle martensite, make steel brittle, so die in use often cracking, chipping, breaking accident; on the contrary the quenching temperature is too low, the dissolution of carbide in the matrix is not full, the hardenability of steel worse, the quenching hardness is low, the use of no wear resistance, low life, at the same time, the compressive strength of steel is also low, prone to upsetting punch or drum and failure
Effect of the cooling conditions of quenching cooling condition. It is also very important. For different mould materials, should be organized according to state requirements, selection of different cooling rate. For high alloy steel, the alloy elements contain more, high hardenability, can the oil cooling, air cooling, even austempering and martempering processes such as, if adopts water cooling quenching is prone to rapid cooling quenching crack; for low alloy die steel, because of its lower hardenability, needs to use the water quenching cold can enhance the cooling speed, the general use of cooling water, if Liu Qi the oil cooling or air cooling, due to the low hardness after quenching, die do not wear, in service life shortened, also can cause early failure.
Plastic mold steel heat treatment have issue will effect Injection molding cost. Because the poor quality mold will effect the mold life and injection molding parts cost
Mould for manufacturing T10 carbon tool steel for cold impact annealing time, in actual use in the mold face many cracks and scrap. The observations show that the microstructure, two carbide in ferrite matrix on the distribution uneven, and there is a lot of graphite precipitated at the grain boundary. The analysis thinks, this kind of graphite by annealing thes teel in the temperature range of 780-800 DEG C when the insulation, long time caused by the.