Nodular cast iron laser hardening technology

Abstract

The invention relates to a laser hardening technology for a nodular cast iron workpiece. The laser hardening technology for the nodular cast iron workpiece comprises the steps of: fast scanning a workpiece surface by using a laser beam with high energy, and fast heating the workpiece surface by using the laser till the temperature of the workpiece surface is in the temperature range between an austenitic phase transition temperature of the workpiece and a melting point temperature of the workpiece. The hardening layer of the nodular cast iron workpiece has fine and dense textures; the hardness and wear-resisting property of the workpiece are largely improved; as laser quenching has a smaller heat affected zone on a substrate, the deformation and cracks of the workpiece are lightened, and the strengthening quality of the workpiece is high; meanwhile, the technological process is easy to realize automatic control.

Description

technical field [0001] The invention belongs to the technical field of laser heat treatment, and specifically relates to a laser processing technology for improving the surface quality of ductile iron, especially the hardness and wear resistance of ductile iron. technical background [0002] Due to its certain plasticity, high strength and wear resistance, ductile iron is widely used in parts with heavy load and complex stress in the machinery industry, such as hydraulic piston pump cylinder; automobile tractor crankshaft, connecting rod, camshaft; Rolling machine rolls, large gears, cylinder blocks; large and small rollers of bridge cranes, etc. Therefore, the surface strengthening of nodular cast iron has high practical value. [0003] Other strengthening methods of ductile iron include: induction heat treatment, electron beam heat treatment, ion beam heat treatment, surface nitriding, surface boronizing, etc. Compared with laser heat treatment, they have some defects: (1...

AI Technical Summary

Problems solved by technology

Compared with laser heat treatment, they have some defects: (1) induction heat treatment has high sensitivity to workpiece section or contour, low energy density, and has electrodynamic effect on molten layer

(2) Electron beam heat treatment requires a vacuum environment, and generally only one workbench can work

(3) There is an electrode effect in ion beam heat treatment, the thermal mode is not easy to change, and the energy density is low

(4) Surface nitriding and surface boronizing have problems such as high cost, long treatment cycle and thin hardened layer

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