The choice of equipment of commonly used heat treatment reachs the defect that h
From;    Author:Stand originally
One. Commonly used heat treatment heat heat choice
Furnace choice

The furnace type that should ask to reach workpiece according to different technology will decide

1. Produce to cannot finalizing the design group by group, workpiece size is unequal, sort is more, have on requirement craft versatility, multi-purpose of the gender, can choose box type furnace.

2. Heat long axis kind reach senior filar staff, when the workpiece such as pipe, can choose electric stove of deep well type.

3. The cementite spare parts of small lot, can choose furnace of cementite of well type gas.

4. The production that waits for a spare parts to gear of the car of large quantities of quantities, tractor is optional continuous cementite product line or box type are multi-purpose furnace.

5. To preform of stamping workpiece plank heat when large quantities of quantities are produced, had better choose scroll furnace, roller bottom furnace.

6. Right group by group finalize the design spare parts, push rod type or furnace of resistor of conveyer belt type can be chosen on production (push rod furnace or casting tape furnace)

7. Small-sized and mechanical spare parts if: Bolt, nut can choose brace up bottom type furnace or net belt furnace.

8. Steel ball and roller heat treatment can be chosen inside the circumgyrate of helix runs furnace.

9. Base of nonferrous metal ingot can use heat of push rod type when large quantities of quantities are produced, and heating furnace of loop of usable to nonferrous metal small part and material air.

2. Heat blemish and control

One) , overheat phenomenon

What we know to overheat heats to bring about austenite grain the most easily in heat treatment process is bulky, make the mechanical function of the spare parts drops.

1. General overheat: Heat temperature exorbitant or grow too in time of the heat preservation below high temperature, cause austenite grain thick change call overheat. Bulky austenite grain can bring about the obdurability of steel to reduce, brittleness transition temperature is elevatory, increase when quenching be out of shape craze tendency. And the cause that causes overheat is out of control of furnace temperature appearance or batch mixing (often happen to do not know craft) . Overheat is organized but classics anneal, normalizing or for many times after high temperature temper, new below normal circumstance abstruse family name is changed make grain is refined.

2. Fracture surface heredity: Have the rolled steel that overheat organizes, heat afresh after quenching, although can make austenite grain is refined, but still appear sometimes fracture surface of bulky grain shape. The academic controversy that generates fracture surface heredity is more, think Ceng Yin heats commonly temperature is exorbitant and make of MnS and so on sundry dissolve enters austenite and interface of rich collect Yu Jing, and these field trash when refrigeration are met again separate out of face of edge crystal boundary, easy edge is bulky when sufferring concussion 奧 body crystal boundary ruptures.
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