Manufacturing method for UNSN08810 iron-nickel-base alloy large-diameter seamless pipe for high temperature heating furnace

An iron-nickel-based alloy, high-temperature heating technology is applied in the field of iron-nickel-based alloy seamless pipe processing, and can solve the problem of not clearly stating the control method of the surface quality of the finished pipe, not involving the front smelting and the manufacturing method of the pipe blank, and the quality of the pipe. It is difficult to meet the problems of high performance and achieve the effect of reducing electroslag process, uniformity of wall thickness and roundness of outer diameter, and uniform internal structure

Active Publication Date: 2018-01-09
宝武特种冶金有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The difficulties in the manufacturing process of UNS N08810 large-diameter seamless pipes (diameter range Φ168mm-φ406mm) mainly include difficult control of heat treatment grain size, high requirements for mechanical properties, difficult control of internal and external surface quality, and defects such as corrosion caused by pickling. The surface is easy to crack when the tube is processed
[0005] Chinese patent CN104328324A discloses a production process of iron-nickel-based alloy pipe, but only involves the processing technology of UNSN08810 iron-nickel-based alloy capillary and finished pipe, does not involve the previous smelting and pipe blank manufacturing method, and does not clearly explain the finished product The control method of the surface quality of the pipe, and the capillary is produced by the hot extrusion process
This process has high manufacturing costs and low production efficiency, and is not suitable for industrial production, nor is it suitable for the production of large-scale round pipes for high-temperature heating furnaces.
[0007] Chinese patent 201010538461.6 discloses a method of centrifugal casting + hot extrusion + cold rolling or cold drawing to process small-diameter thin-walled nickel-based alloy pipes. Meet the requirements of high performance, and only provide a small-caliber thin-walled nickel-based alloy pipe processing method, and the cost of hot extrusion is high

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0049] Specifications are Preparation of UNS N08810 Large Diameter Tubing.

[0050] 1) The ingot is forged into an intermediate round tube billet

[0051] Adopt the method for electric arc furnace smelting, smelt out the following UNSN08810 alloy square ingot of chemical composition (weight percentage):

[0052] C: 0.05%, P: 0.005%, S: 0.002%, Si: 0.3%, Mn: 0.5%, Cr: 19.0%, Ni: 30.0%, Cu: 0.50%, Al: 0.15%, Ti: 0.15%, Al+Ti: 0.30%, Fe≥39.5%, and the rest are unavoidable impurities.

[0053] Dimensions of UNS N08810 alloy ingot: height × width × length = 200 × 500 × 3000mm. Heat the smelted square ingot, and then forge it to anise with a fast forging press, with a deformation of 60%, and then send it to the heating furnace for heating, and finally forge it to a 241mm black leather forging rod with a radial forging machine, and then turn it off after air cooling (that is, the middle round tube), the surface finish of the middle round tube is Ra≤1.6μm.

[0054] 2) heat perfo...

Embodiment 2

[0075] Specifications are Preparation of UNS N08810 Large Diameter Tubing.

[0076] 1) The ingot is forged into an intermediate round tube billet

[0077] Adopt the method for electric arc furnace smelting, smelt out the following UNSN08810 alloy square ingot of chemical composition (weight percentage):

[0078] C: 0.05%, P: 0.005%, S: 0.002%, Si: 0.2%, Mn: 0.5%, Cr: 19.0%, Ni: 30.0%, Cu: 0.20%, Al: 0.15%, Ti: 0.15%, Al+Ti: 0.30%, Fe≥39.5%, and the rest are unavoidable impurities.

[0079] Dimensions of UNS N08810 alloy ingot: height × width × length = 200 × 500 × 3000mm. Heat the smelted square ingot, and then forge it to anise with a fast forging press, with a deformation of 60%, and then send it to the heating furnace for heating, and finally forge it to a 241mm black leather forging rod with a radial forging machine, and then turn it off after air cooling (that is, the middle round tube), the surface finish of the middle round tube is Ra≤1.6μm.

[0080] 2) The middle...

Embodiment 3

[0107] Specifications are Preparation of UNS N08810 Large Diameter Tubing.

[0108] 1) The ingot is forged into an intermediate round tube billet

[0109] Adopt the method for electric arc furnace smelting, smelt out the following UNSN08810 alloy square ingot of chemical composition (weight percentage):

[0110] C: 0.05%, P: 0.005%, S: 0.002%, Si: 0.3%, Mn: 0.4%, Cr: 19.0%, Ni: 30.0%, Cu: 0.30%, Al: 0.15%, Ti: 0.15%, Al+Ti: 0.30%, Fe≥39.5%, and the rest are unavoidable impurities.

[0111] Dimensions of UNS N08810 alloy ingot: height × width × length = 200 × 500 × 3000mm. The smelted square ingot is heated, and then forged to octagonal by fast forging press, with a deformation of 40%, and then sent to the heating furnace for heating, and finally forged by radial forging machine to Black leather forging rod, after being air-cooled, machine polished (that is, the middle round tube billet), the surface finish of the middle round tube billet is Ra≤1.6μm.

[0112] 2) The mid...

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Abstract

Disclosed is a manufacturing method for a UNSN08810 iron-nickel-base alloy large-diameter seamless pipe for a high temperature heating furnace. The manufacturing method comprises the following steps that firstly, a square ingot which meets requirements is directly continuous-casted by using an electric arc smelting method, then the square ingot is cogged, then a hollow billet is produced by usinga hot piercing process, finally, through a cold machining process, a matched heat treatment process and a supplemented pipe surface treatment process, and the texture of the pipe is controlled to be uniform, so that the pipe has high performance and high surface quality. The microscopic structure of the pipe is isometric crystal, the grain size is 3-5 grades, the tensile properties of a finished pipe at room temperature are that the tensile strength is equal to or greater than 500 MPa, the yield strength is equal to or greater than 210 MPa, and the elongation is equal to or greater than 50%, and the tensile properties at 650 DEG C are that the tensile strength is equal to or greater than 400 MPa, the yield strength is equal to or greater than 120 MPa, and the elongation is equal to or greater than 50%.

Description

technical field [0001] The invention belongs to the technical field of processing iron-nickel-based alloy seamless pipes, and in particular relates to a method for manufacturing UNSN08810 iron-nickel-based alloy large-diameter seamless pipes for high-temperature heating furnaces. Background technique [0002] Iron-nickel-based alloy is an alloy between high-nickel austenitic stainless steel and nickel-based alloys. Compared with nickel-based alloys, it can save nearly 40-50% of nickel. Under the premise of ensuring that the alloy matrix has a face-centered cubic structure austenite structure, iron-nickel-based alloys can accommodate more nickel than chromium-nickel austenitic stainless steel. It is beneficial to improve the corrosion resistance of the alloy and the content of chromium, molybdenum and other elements, and the thermal stability of the alloy is generally better than that of chromium-nickel austenitic stainless steel with high chromium and high molybdenum. In vi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B23P15/00C21D8/10C22C30/02C22C38/02C22C38/04C22C38/06C22C38/42C22C38/50C23G1/08C23G1/10
Inventor 欧新哲马明娟
Owner 宝武特种冶金有限公司
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