Method and apparatus for heat treatment of ferrous materials using energy beams

Abstract

The present invention relates to a method and an apparatus for heat treatment of objects, such as for hardening objects with complex shapes, such as crankshafts. The method comprises the steps of: projecting an energy beam (1), such as a laser beam, onto the surface of an object (1000); operating a scanner (2) to scan said beam (1) repeatedly so that the original spot (11) according to The first scan pattern is displaced to create an effective spot (12) on the surface of the object; and the effective spot (12) is displaced relative to the surface of the object (1000). The beam follows an optical path between the scanner (2) and the surface of the object (11), and a beam deflecting device (3, 3A) is arranged in the optical path for redirecting the beam. The beam deflecting device may be arranged close to the surface of the object.

Description

technical field [0001] The present invention relates to the treatment of objects with energy beams, eg for the purpose of hardening one or more surface portions of the object. Background technique [0002] It is well known in the art to perform thermal treatment of objects using energy beams, such as laser beams, for example, to heat ferrous materials to high temperatures below their melting temperature, followed by quenching, i.e. cooling them rapidly enough to form Hard martensite, which hardens ferrous materials such as medium carbon steels. Heat treatment with energy beams is also known for other purposes, eg for softening one or more selected parts of a previously hardened object, such as a sheet metal object. [0003] For example, case hardening can be used to increase the wear resistance of a material and sometimes also to increase the fatigue strength caused by residual compressive stresses. Surface hardening may be useful for hardening surfaces that will be subjec...

AI Technical Summary

Problems solved by technology

However, while this process has proven useful for achieving the desired hardening, it has some drawbacks

For example, inductors that generate heating by induction have to be designed according to the specific configuration of the crankshaft, which reduces flexibility: adapting induction machines to new types of crankshafts can be time-consuming and costly

Also, heating by induction is costly in terms of the energy required to heat the crankshaft to the desired level

Additionally, the cooling process is complex, costly and challenging from an environmental standpoint due to the large volumes of cooling fluid used

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