Method to produce high corrosion and wear resistant cast iron components by using laser cladding
A method to produce a wear and corrosion resistant coating system onto a surface of a substrate, preferably a brake disc, comprising the following steps: (1) providing the substrate having the surface made of an iron-based material or a steel material, (2) selecting a dedicated material for producing one or more coating layers of the coating system, (3) producing onto the substrate surface one or more coating layers of the coating system by using a laser cladding process, wherein the dedicated material selected in step (2) is used as source material for the production of the coating layers, and positioning a laser beam with respect to the substrate surface in such a manner that a coating angle is formed between the laser beam and the substrate surface, and maintaining this coating angle during the production of the one or more coating layers at a value between 10° and 30°.
1 . A method to produce a wear and corrosion resistant coating system onto a surface of a brake disc, the method comprising the following steps:
(1) providing the brake disc having the surface to be coated with a coating system,
(2) selecting a dedicated material for producing one or more coating layers of the coating system,
(3) producing onto the brake disc surface to be coated one or more coating layers of the coating system by using a laser cladding process, wherein the dedicated material selected in step (2) is used as a source material for the production of the coating layers,
wherein for conducting step (3) a laser beam is positioned with respect to the brake disc surface to be coated in such a manner that an angle is formed between the laser beam and an axis perpendicular to the brake disc surface to be coated, and this angle is called a coating angle, and the coating angle is maintained during the production of the one or more coating layers at a value between 10° and 30°, and
wherein the brake disc or at least the surface of the brake disc is made of an iron-based material or a steel material and wherein the dedicated material is fed into the laser beam above the brake disc, and
wherein the coating system has a total thickness between 150 and 500 μm, a porosity according to ASTM E2109-09≤0.5% and average microhardness of 305 HV.
2 . The method according to claim 1 , wherein the brake disc material is a cast iron material.
3 . The method according to claim 2 , wherein before conducting the step (3), a pre-treatment process is conducted, said pre-treatment process comprising a step in which graphite lamellae are reduced or removed from the brake disc for increasing weldability of the brake disc material.
4 . The method according to claim 3 , wherein the pre-treatment process involves surface activation of the brake disc material by using a pulsed fluid jet process.
5 . The method according to claim 1 , wherein the laser cladding process in step (3) is conducted by implementation of high laser power levels which are in a range between 10 KW and 30 kW.
6 . The method according to claim 1 , wherein the laser cladding process in step (3) is conducted by using high process speeds which are in a range between 100 m/min and 200 m/min.
7 . The method according to claim 1 , wherein the laser cladding process in step (3) is conducted by depositing the selected material at a deposition rate between 500 cm 2 /min and 1200 cm 2 /min.
8 . The method according to claim 1 , wherein the coating system comprises only one coating layer produced by using laser cladding.
9 . The method according to claim 8 , wherein the coating system consists of the only one coating layer produced by using laser cladding.
10 . The method according to claim 1 , wherein the coating system comprises two or more coating layers produced by using laser cladding.
11 . The method according to claim 10 , wherein the coating system consists of the two or more coating layers produced by using laser cladding.
12 . The method according to claim 1 , wherein after conducting the step (3), a post-treatment process is conducted, said post-treatment process comprising using a nitrocarburizing process to produce a diffusion layer on the brake disc, in order to protect uncoated surfaces of the brake disc.
13 . The method according to claim 1 , wherein after conducting the step (3), a post-treatment process is conducted, said post-treatment process comprising using a nitrocarburizing process and an oxidation process to produce at least one diffusion layer and at least one oxidation layer on the brake disc in order to improve corrosion and wear resistance of uncoated surfaces of the brake disc.