Company Name:
Lishui Huanqiu Bearing Trading Co., Ltd.
Company Address:
No.11 Shiting Road, Shuige Industrial Zone,Lishui, Zhejiang,China
Contact Person: William
Email: admin@tradebearings.com
Homepage: www.asiabearings.com
Bearing B2B: www.tradebearings.com
(1) the impact of the internal stress
Under normal circumstances,
quenching the distortion of the parts including the size change and the
geometry changes, but regardless of what kind of distortion, mainly due to
quenching parts internally generated internal stress caused by the Depending on the causes of internal stress, is divided into
the thermal stress and organizational stress. Parts of the quenching distortion mainly two kinds of stress
affect the results if the stress is greater than the material yield limit, will
be a permanent distortion. Quench the thermal stress and
organizational stress are the most concentrated period of time, especially the
hardening agent is impure or cooling capacity is too strong, causing more
internal stress, the distortion is more serious. Pre-quench parts, thermal stress of work; play a leading role
in the post-quench, is the stress. For bearing steel, due to its low Ms point, more residual
austenite, so the quenching distortion is mainly thermal stress distortion.
(2) The influence of part size and shape
Generally speaking, part cross-section symmetry, thickness
less, then the distortion comparison rules, even. The contrary is part quenching
in addition to all parts of the exterior cooling, the parts between the cooling
is very uneven, angular, and the thin edge of the cooling faster, depression or
groove at the cooling is slow. It can be conclude that: parts
of the section shape asymmetry under thermal stress and distortion performance
of the fast cold raised; not harden ability slow cold conditions, the
distortion will also be the case; In slow the cold harden ability conditions, part distortion
performance in the role of organizational stress as raised to the slow cold.
For the above-mentioned parts,
each-part uneven parts in the heating and cooling between the various parts of
the structure there is a larger temperature difference, a very obvious tendency
of quenching distortion in the process of heating and cooling should take
appropriate measures to reduce the extent of the distortion.
The impact of the machining
Machining, cutting the amount
of different parts of each part of the processing, will inevitably lead to
parts subject to tensile stress, while another part is subject to compressive
stress. Cutting, the more stress is greater. Before quenching, such as not stress is eliminated,
additional distortion will occur in the quenching.
(4) Heat treatment process
moderately reduce the
quenching temperature thermal stress and stress are reduced accordingly, thus
to some extent, to avoid part distortion. In addition, the cooling stage, reducing the cooling rate
below the Ms point, can also be reduced due to the stress caused by the
distortion.
