Method for solution hardening of a cold deformed workpiece of a passive alloy, and a member solution hardened by the method

A cold deformation and alloy technology, applied in metal material coating process, solid diffusion coating, coating and other directions, to achieve the effect of less time execution and good corrosion resistance

Active Publication Date: 2014-12-24
EXPANITE TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although metal treatment according to PA2011 70208 provides superior properties compared to other methods of the prior art, it is doubtful that further improvements in metal properties can be obtained

Method used

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  • Method for solution hardening of a cold deformed workpiece of a passive alloy, and a member solution hardened by the method
  • Method for solution hardening of a cold deformed workpiece of a passive alloy, and a member solution hardened by the method
  • Method for solution hardening of a cold deformed workpiece of a passive alloy, and a member solution hardened by the method

Examples

Experimental program
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Effect test

example 1

[0081] Lock and key washers of cold deformed austenitic stainless steel (AISI316) are hardened by two methods of the prior art.

[0082] Two identical key washers of cold-formed austenitic stainless steel (AISI316L) were hardened. FIG. 2 shows a key washer set 1 of said key washer 2 and its use. Each washer 2 has a first side 3 with radial teeth 4 and an opposite cam side 5 with a cam 6 . During use of the key lock washer set 1 , the washer 2 is placed facing each other with the cam side 5 as shown. The two lock and key washers are solution hardened using nitrogen and carbon at a temperature of 440°C. One gasket was hardened using the method disclosed in PA2011 70208, ie in a high temperature process followed by a low temperature process, and the other gasket was directly case hardened using the same low temperature process, ie prior art. The gasket was analyzed using an optical microscope. image 3 and Figure 4 Shown on the left is a gasket surface hardened only using a...

example 2

[0085] Cold deformed austenitic stainless steel (AISI 316) was hardened by methods of the prior art as well as methods disclosed in PA2011 70208.

[0086] Two identical parts (back ferrules) of cold deformed austenitic stainless steel (AISI316) were solution hardened using nitrogen and carbon at a temperature of 440°C. One part was hardened using the method disclosed in PA2011 70208, ie in a high temperature process followed by a low temperature process, and the other part was directly case hardened using the same low temperature process. Figure 5 On the left is shown a microstructural analysis using an optical microscope of a part that was case hardened using only the nitrocarburizing process using a gas containing nitrogen and carbon at a temperature of 440°C 12 hours at atmospheric pressure. The outer surface in the nitrogen-containing region exhibits partial sensitization with significant CrN precipitates appearing on the outermost surface. Figure 5 On the right is sho...

example 3

[0088] Cold deformed austenitic stainless steel (AISI 304) plates were hardened by methods of the prior art as well as methods disclosed in PA2011 70208.

[0089]Two identical cold-rolled (deformed) austenitic stainless steel (AISI 304) plates were solution hardened using nitrogen and carbon at a temperature of 440°C. One part was hardened using the method disclosed in PA2011 70208, ie in a high temperature process followed by a low temperature process, and the other part was directly case hardened using the same low temperature process. Figure 6 Shown on the left is a part surface-hardened only using the nitrocarburizing process using a gas containing nitrogen and carbon at a temperature of 440°C for 20 hours and subsequently exposed to The corrosion test was carried out in 14% sodium hypochlorite solution for 70 minutes. Figure 6 On the right a part hardened with the method disclosed in PA2011 70208 is shown. The part is exposed to a nitrogen-containing atmosphere at a t...

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Abstract

The invention relates to a method for method for solution hardening of a cold deformed workpiece of a passive alloy containing at least 10% chromium, which method comprises -dissolving at least nitrogen in the workpiece at a temperature T1, which is higher than the solubility temperature for carbide and/or nitride and lower than the melting point of the passive alloy, wherein dissolution of nitrogen at temperature T1 is performed to obtain a diffusion depth in the range of 0 mum to 5 mm, and -cooling the workpiece after the dissolution step at temperature T1 to a temperature which is lower than the temperature at which carbides and/or nitrides form in the passive alloy, wherein the cooling step takes place in an inert gas not containing nitrogen. The invention further relates to a member, such as a lock washer for securing bolts or nuts prepared using the method.

Description

technical field [0001] The invention relates to a method for solution hardening of cold deformed workpieces of passive alloys. The method provides a hardened alloy in which substantially no carbides and / or nitrides are formed. The method also provides a corrosion-resistant surface while maintaining the core strength of the material obtained from cold deformation. The invention further relates to components solution-hardened by this method. These components are particularly relevant to the medical, food, automotive, chemical, petrochemical, pharmaceutical, marine, packaging, watch, cutlery / cutlery, medical, energy, pulp and paper, mining, or wastewater technology fields. Background technique [0002] Stainless steel and other passive alloys are typically materials with good corrosion resistance but relatively poor tribological characteristics, such as adhesive wear characteristics. To solve this problem, stainless steels and comparable alloys can be case-hardened at low te...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23C8/26C23C8/34
CPCC23C8/02C23C8/24C23C8/26C23C8/30C23C8/32C23C8/34C23C8/80
Inventor T·L·克里斯琴森T·S·胡梅尔肖M·A·J·索默斯
Owner EXPANITE TECH
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