Novel high-nitrogen austenitic stainless steel for non-magnetic drill collar and manufacturing method of novel high-nitrogen austenitic stainless steel

A high-nitrogen austenite and non-magnetic drill collar technology, applied in the field of stainless steel materials, can solve the problems of deterioration of plasticity and toughness of stainless steel, and achieve excellent performance and excellent resistance to intergranular corrosion

Active Publication Date: 2017-05-24
CENT IRON & STEEL RES INST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

On the contrary, the addition of Mo element will lead to the formation of some brittle precipitates such as sigma phase or chi phase, which seriously deteriorates the plasticity and toughness of stainless steel, so the content of Mo element is controlled at a reasonable level

Method used

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  • Novel high-nitrogen austenitic stainless steel for non-magnetic drill collar and manufacturing method of novel high-nitrogen austenitic stainless steel
  • Novel high-nitrogen austenitic stainless steel for non-magnetic drill collar and manufacturing method of novel high-nitrogen austenitic stainless steel
  • Novel high-nitrogen austenitic stainless steel for non-magnetic drill collar and manufacturing method of novel high-nitrogen austenitic stainless steel

Examples

Experimental program
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Effect test

Embodiment 1

[0056] Example 1: Effects of C and N elements on the tensile properties at room temperature of a new type of high-nitrogen austenitic stainless steel for non-magnetic drill collars

[0057] The tensile properties of the new high-nitrogen austenitic stainless steel samples for non-magnetic drill collars with different C and N elements were tested according to the American Society for Testing and Materials standard ASTM-E8 at room temperature. The results show that when the final forging temperature is 1000℃, the room temperature tensile strength of the material ( figure 1 ) and yield strength ( figure 2 ) all increased with the increase of the sum of C element and N element content. In particular, when the total content of C and N elements is 0.72%, although the tensile strength can meet the material standard requirements (1035MPa), its room temperature yield strength cannot meet the standard requirements (965MPa). When the total content of C and N elements rises to 0.75%, i...

Embodiment 2

[0059] Example 2: Influence of C and Cr elements on intergranular corrosion performance of new high-nitrogen austenitic stainless steel for non-magnetic drill collars

[0060] The new high-nitrogen austenitic stainless steel samples with different C and Cr contents for non-magnetic drill collars were tested for their intergranular corrosion performance according to the E method of the American Society for Testing and Materials standard ASTM-A262. In the test, all samples were tested in two states of wrought state (no solid solution) and sensitized state. The results show that all the samples in forged state (no solid solution) without sensitization treatment passed the test, but after the sensitization test, only some samples passed the test (Table 2). It can be seen from the Cr content of all samples that increasing the Cr content helps to improve the intergranular corrosion resistance of the material. This is mainly caused by the local diffusion of Cr element during the sen...

Embodiment 3

[0064] Embodiment 3: the impact of heating temperature on the generation of harmful precipitates

[0065] Cr carbides are one of the most harmful precipitates in high nitrogen austenitic stainless steels that have the greatest impact on hot working. A new type of high-nitrogen austenitic stainless steel sample for non-magnetic drill collars was subjected to aging treatment at different temperatures and times to observe the precipitation of Cr carbides. The temperature of the aging treatment mainly revolves around the critical temperature range (920°C-980°C) of the thermal deformation process. After aging treatment for different times from 10min to 60min, the amount of carbide precipitation below 940°C is relatively large ( Figure 5-8 ), and when the aging temperature rises above 960 °C, the precipitation rate and total amount of carbides are greatly reduced. The results of the statistical distribution of precipitates show this trend more clearly ( Figure 9 ). Therefore, ...

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Abstract

The invention relates to novel high-nitrogen austenitic stainless steel for a non-magnetic drill collar and a manufacturing method of the novel high-nitrogen austenitic stainless steel, and belongs to the technical field of stainless steel materials. The stainless steel comprises, by weight, 22.15-23.50% of Cr, 0.56-0.68% of Mo, 0.047-0.060% of C, 0.70-0.81% of N, 0.95-2.14% of Ni, 16.20-16.94% of Mn, 0.17-0.24% of Si, 0.008-0.010% of P, 0.008-0.012% of S, and the balance Fe, wherein the C+N is greater than or equal to 0.747% but smaller than or equal to 0.836% by weight, and Cr+3.3*Mo+16.0*N is greater than or equal to 35.0% by weight. The manufacturing method comprises the steps of non-vacuum induction melting, argon oxygen decarburization external refining, cogging by a quick forging press, molding by a radial forging machine, and water-cooling treatment. The novel high-nitrogen austenitic stainless steel for the non-magnetic drill collar has the advantages of excellent indoor temperature strength and intercrystalline corrosion resistance.

Description

technical field [0001] The invention belongs to the technical field of stainless steel materials, in particular to a novel high-nitrogen austenitic stainless steel for non-magnetic drill collars and a manufacturing method thereof. Background technique [0002] Non-magnetic drill collars are important components for high-precision, high-depth land and offshore oil and gas drilling at home and abroad. Generally speaking, the drill collar is one of the main components of the drill string in the drilling and production components, which has the function of providing drilling pressure to the drill bit and improving the rigidity of the drill string. At present, the non-magnetic drill collar is a hollow thick-walled pipe made of stainless steel with a very low relative magnetic permeability (<0.01), which provides a magnetic shielding environment for the normal operation of the measurement while drilling (MWD) equipment. Guaranteed real-time correction of drilling direction. A...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/58C22C38/02C22C38/44C21D8/06C21D6/00
CPCC21D6/004C21D6/005C21D8/065C21D2211/001C22C38/001C22C38/02C22C38/44C22C38/58
Inventor 屈华鹏郎宇平陈海涛
Owner CENT IRON & STEEL RES INST
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