TW201107497A - An aging precipitation hardened stainless steel - Google Patents

Abstract

An aging hardened stainless steel, the alloy of by the following chemical composition: Max 0.07 wt% C, Max 1.0wt % Si, Max 0.8 wt% Mn, Max 0.03 wt% P, Max 0.03 wt% S, 9 to 12 wt% Cr, 6 to 8 wt% Ni, 4.5 to 6.5 wt% Mo, 9 to 12 wt% Co, 1.0 to 3.5wt% Cu, other are approximately Fe. This alloy hardness for annealing approximately HRC 33 to 36. This alloy hardness by solution + aging (heat treatment) approximately HRC 48 to 51, and the tensile strength situated approximately 1700 Mpa, Elongation up to 8%, Corrosion-resistant over than 72 hour corrosion test. This alloy major crystallized structure is martensite structure + residual austenite structure.

Description

201107497 VI. Description of the Invention: [Technical Field] The present invention relates to a type of granulated iron-type precipitation hardenable stainless steel having high strength, high _ and anti-aliasability, and particularly the alloy material of the present invention is applicable to I Casting 蛰 蛰 'suitable for a variety of high-corrosion resistance and high strength and high secrets. [Prior Art] At present, the market demand for high-resistance, high-strength and high-secure cast stainless steel alloy materials - generally the precipitation hardening type is not preferred, such as the side CB7Cu-b ASTM meU-2 'disambiguation _ + anti-antibody M Duo can only reach 1400 MPa. 'In the environment with higher demand intensity, often no alternative materials can be found; or it needs to increase the cross-sectional area, ribs and other ways to reinforce, not only increase the material cost, but also the appearance is more cumbersome. SUMMARY OF THE INVENTION (7) In order to improve the above problems, the alloy of the present invention is made of a high purity raw material. In the process, the alloy component content is adjusted in accordance with the purpose of the present invention to achieve the desired mechanical properties. Λ Chromium (Cr · 9~12wt〇/0) provides corrosion resistance in precipitation hardening without recording steel, but more chromium reduces the toughness of precipitation hardened stainless steel. A nickel (Ni: 6 to 8 wt%) increases the toughness of the material. Drilling (C〇: 9~12%) combined with other elements to form C〇-M〇-Cr-Cu 201107497 output strengthening alloy base and increase toughness; too much cobalt affects metamorphism of 麻田散铁, resulting in alloy strength reduce. Gu (Mo: 4.5~6.5wt%) can increase the ductility and corrosion resistance of the material, but too much care causes the iron phase of the Worthfield to remain. Copper (Cu: 1.0 to 3. 5 wt%) forms a precipitation strengthening with cobalt, and excessive copper causes the alloy to be hard and brittle. [Embodiment] In the above process, the inventors have experimentally analyzed and tested a plurality of castable stainless steel alloy materials having ultra high strength and high corrosion resistance, and the optimum distribution thereof is shown in Table 2. As shown in Table 2, the alloy of the present invention has a hardness of up to 51HRC and a tensile strength of up to 9.7 MPa at a solid solution of 925 ° C + _73 ° C cryogenic + H1000 aging precipitation, and the elongation can reach 9%. The nature of the money is 5v^%Να〇1+95Λνί%Ιΐ2〇 under the salt spray test >14砸. The metallurgical structure of the alloy steel belongs to the Ma Tian loose iron structure + a small amount of Osda iron organization. Compared with the same type of steel ASTM CB7Cu - regardless of the strength or elongation of the performance of the transcendence, the strength of the product cast by the alloy steel of the present invention, the chapter knife and the _ recorded the most present, for the high wealth The best choice for green non-mineral steel castings. 201107497

Alloy Type ASTM CB7CU-1 ASTM CB7Cu-2 Hardness (HRC) 41 40 Tensile Strength (MPa) 1370 1320 Depth Strength (MPa) 1200 1150 Elongation (%) >7 >6 Resistance #性性>72HR > 72HR Table 1

C Si Mn PS Cr < 0.07 < 1.0 < 0.8 < 0.03 < 0.03 9/12 Ni Mo Co Cu Fe 6/8 4.5/6.5 8/12 1.0/3.5 Bal. Table 2 Unit: wt% 201107497 Condition Solid solution solid solution + cryogenic + aging (H950) solution + cryogenic + aging (Η 1000) solution + cryogenic + aging (Η 1050) hardness (HRC) 32 ~ 36 47.6 ~ 48.3 48.2-51.1 47.8 ~ 49.7 tensile Strength (MPa) 1105~1160 1594~1670 1663~1726 1623~1680 Falling strength (MPa) 866~893 1431~1514 1548~1601 1512-1567 Elongation (%) 10.1-12.3 6·6 〜8·1 7.1- 8.6 8.9 ~ 9.5 Shrinkage ratio (%) 46-53 33 ~ 40 31 ~ 44 43 ~ 51 Corrosion resistance (HR) >144 >144 >144 >144

Solid solution = 925 ° C / 1 HR deep cooling = -73 ° C / 8HR 201107497 [Simple diagram description] [Main component symbol description]

Claims (1)

201107497 VII. Patent application scope: 1. A precipitation hardening stainless steel is an alloy composed of the following chemical components: at most 0.07% of charcoal (〇, at most l.Owt% of Shi Xi (Si)' at most 〇. 8wt% (Μη), up to 0.03 wt% of structure (Ρ), up to 0.03 wt% of sulfur (5), 9 to 12 wt%/〇 of chromium (Cr), 6 to 8 wt% of nickel (Ni), 4.5 to 6.5 wt% Molybdenum (Mo), 9 to 12% of the inscription (Co), 1. 〇 to 3.5 wt% of copper (Cu), and the remainder is roughly iron (jpe). 2. According to the scope of the patent application! One of the precipitation hardening non-ferrous steels mentioned in the item, the metallographic structure of the alloy is the granulated iron + residual Osbane iron structure. 3. According to the precipitation hardened non-ferrous steel described in item i of the patent application scope, the alloy is required to be more than 72 hours in females under the test of 5 wt% NaC1 + 95 wt% H2G. 4. According to the scope of the application, the above-mentioned type of pine 敎 Lu Li 4 Gan ~ U Tan precipitation hardened stainless steel, the alloy after the treatment of its tensile strength needs to be greater than 17 〇〇 _ hardness should be greater than the side RC. The extension is greater than the catch,