FIELD OF THE INVENTION

The present invention belongs to the technical field of high-temperature alloys, and in particular provides a cobalt-chromium-molybdenum alloy with high wear resistance.

BACKGROUND OF THE INVENTION

There are two main sets of cobalt-based alloys: cobalt-chromium-tungsten (CoCrW) and cobalt-chromium-molybdenum (CoCrMo). The cobalt-chromium- tungsten (CoCrW) series of alloys are resistant to high temperatures and have excellent wear resistance, but inadequate corrosion resistance, whereas the cobalt-chromium-molybdenum (CoCrMo) series of alloys are resistant to high temperatures and have excellent corrosion resistance, but inadequate wear resistance.

The following table shows standard component ranges and hardness indices for common cobalt-chromium-molybdenum (CoCrMo) series alloys in China and abroad:

1 YY0605. 12-2007/ISO5832-12:1996

Table 1 Unit: Wt%

2 ASTM F75-07 and ASTM1537-08

Table 2 Unit: Wt%

SUMMARY OF THE INVENTION

The object of the present invention is to provide a CoCrMo alloy with high wear resistance, which solves the problem of inadequate wear resistance in existing CoCrMo alloys well. The product can be manufactured by casting, forging or powder metallurgy, etc. It can meet the requirements of the zinc industry, etc., or of demanding industrial environments where resistance to high temperatures, corrosion and wear are all required. It can satisfy the requirements of the jewellery industry for products such as rings, bracelets and watch cases to be scratch-resistant and shinier, and can be used to manufacture sputtering targets for electroplating, wherein a compact and shiny surface layer with high wear resistance is formed by physical vapour deposition, satisfying the higher demands people place on the appearance, colour, lustre and impression of jewellery.

The present invention is an alloy material in which cobalt is the matrix, with the weight percentages of the component elements thereof being as follows: chromium Cr: 24 - 35%; molybdenum Mo: 5 - 20%; carbon C: 0.35 - 2.5%; nickel Ni: 0 - 4%; iron Fe: 0 - 4%; silicon Si: 0 - 2%; manganese Mn: 0 - 2%; with the remainder being cobalt Co and other unavoidable impurity elements and process elements.

Solid solution strengthening is the main method used to strengthen common cobalt-chromium-molybdenum (CoCrMo) series alloys in China and abroad, with materials formed by this strengthening method having a maximum hardness of about HRC35. In the CoCrMo alloy with high wear resistance to which the present invention relates, two improvements are made which build upon solid solution strengthening. The first is increased weighting in the solid-solution-strengthened alloy, such as a significantly increased Mo content in the solid-solution-strengthened alloy. The second is a significantly increased content of C amongst the components, leading to the formation of a large amount of carbides in the material. The various carbides have a far higher microhardness than the solid solution, so a significant increase in the hardness of the material is achieved, solving the problems of existing CoCrMo alloy products in having insufficient hardness and inadequate wear resistance despite resistance to oxidation and corrosion.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The above-mentioned domestic and foreign CoCrMo alloy materials have a hardness range of HRC 25 - 35, so the wear resistance thereof is clearly inadequate.

Materials were mixed in the component proportions given below, steel ingots were produced by vacuum casting, and the hardness of the alloys produced were tested. The results are shown in Table 3:

Table 3 Wt%

In summary, the CoCrMo alloy with high wear resistance to which the present invention relates has a hardness range of 36 - 65 HRC.