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Process for Local Hardening

A local quenching and partial technology, which is applied in the field of local quenching, can solve the problems of mechanical property change, long process time and low economy

Pending Publication Date: 2021-03-16
ROBERT BOSCH GMBH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0008] The disadvantages of this solution are that, on the one hand, the overall heat treatment of the component has undesirable side effects, such as deformations, changes in the mechanical properties, or the like; resulting in less economical

Method used

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  • Process for Local Hardening
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Examples

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Embodiment Construction

[0026] figure 1 A temperature-time diagram is shown for an exemplary embodiment of the method according to the invention for induction hardening, the method being carried out in three steps A, B, C. The three steps are: localized, short-time induction diffusion annealing A; localized recrystallization by pearlitization B; and finally localized induction hardening C. Here, these method steps are assigned a separate time: Diffusion annealing time t A , recrystallization time t B and induction hardening time t C .

[0027] In the example shown, the temperature T of the localized diffusion anneal A A Slightly lower than induction hardening temperature T C . The temperature T C About 1050°C. In the example shown, the temperature T of the intermediate step "Recrystallization by pearlitization" B B About 650°C. In the example shown, diffusion annealing t A The length of time is the length of induction hardening t C About 40-50% of that. In the example shown, the duration...

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Abstract

The invention relates to a process for the local hardening of a workpiece by means of local induction hardening.

Description

technical field [0001] The invention relates to a method for local hardening of workpieces according to the preamble of claim 1 . Background technique [0002] In order to improve the wear resistance of workpieces, these workpieces, such as shafts, cylinders, control slides, valve seat geometries or edges of valves, are subjected to induction heat treatment. Here, the raw material is mostly steel or cast steel with a uniform microstructure. [0003] Hydraulic valves are often made of cast iron of different qualities in terms of control edges and seat geometry. The demands on the wear resistance of such geometries are constantly increasing. According to the prior art, these requirements can be met by partial hardening by means of induction heat treatment (WBH). [0004] The cast iron material used is significantly more heterogeneous than steel and cast steel. However, the initial state is likewise initially present in a ferrite / pearlite ratio which can fluctuate greatly d...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D1/18C21D1/26C21D9/00
CPCC21D1/18C21D1/26C21D9/0068C21D2221/00C21D1/42C21D5/00Y02P10/25C21D2211/009
Inventor H·奥滕里特M·汉泽尔M·策辛格T·瓦尔登迈尔
Owner ROBERT BOSCH GMBH