The main factors influencing the manufacturability, thermal and chemical-thermal treatment

The choice of material. Depending on the working conditions, nature of loading and shapes of parts, the designer selects the appropriate material during the subsequent treatment must ensure that the calculated set of properties. Choosing the material, consider the following: guaranteed mechanical properties depending on the conditions of work products; technology of processing in all process stages prior to heat treatment; hardenability, minimal distortion and a lead of the part during heat treatment. Low-alloy steels provides higher mechanical properties compared to carbon, due to this you can reduce the weight and dimensions of the parts. In addition, these steels are characterized by high processability during heat treatment, giving smaller, a marriage of cracks and leash. When selecting heat treatment, take into account the nature of the work products, types of loads, changing of properties on the section and accuracy class of manufacturing parts. For example, to obtain high hardness and resistance to wear (work with non-impact load and bending) it is rational to apply the nitriding. If these properties should not be high requirements, then apply more simple and less long-term processes — the cementation, or cyanidation. In some cases, these processes are replaced by more technologically advanced heat treatment with heating, T. V. h

Application of progressive methods of heat treatment (bright isothermal quenching, vacuum treatment, treatment in protective environments, undeformation heat treatment) reduces the overall manufacturing cycle parts and provides high product quality. The design of products necessary to carry out the unification of the material and apply heat treatment to provide a rational limit on the number of materials and hardness values within the same type of material. This will allow to mechanize the process of heat treatment and to reduce the cost of production.

Warping of parts and adaptability of the forms during heat treatment. Warping and leash components during heat treatment occur due to uneven increase in the specific volume of structural components of steel by heating-cooling and appearance as a result of internal stresses.

Small simple items (without sharp corners and abrupt transitions) are less prone to warping than long with a variable cross section and an open-circuit.

The deformity is sometimes so considerable that the item is discarded; in some cases this can be corrected by straightening or edit. Therefore, the design should give the details of such structural forms that would reduce warpage. Details of a more complex form, it is more expedient manufacturing of alloy steels, hardened izotermicheskoi or oil.

Heat treatment of large flat or long parts to eliminate the leads perform special quenching presses with subsequent thermofixation vacation.

To reduce the deformation and crack formation it is necessary:

to choose the right material;
to assign a heat treatment, which provides the minimum leash (or stepped isothermal quenching);
transitions from one section of a part to another to make smooth; mass of metal needs to be distributed evenly unwanted long open grooves and undercuts;
to ensure manufacturability forms for cycles to manufacture the part before heat treatment;
if necessary, to provide technological allowances (in coordination with the technology-the treater), the deletion of which machining will correct the size and shape of the part.

Technologist-treater depending on the composition of the steel, the shape of the part and the desired properties selects the best method of quenching (isothermal, stepwise, intermittent), in which the deformation is minimal.