Method for improving deformation coordination capacity in 40Cr / Q345B stretching process

Abstract

The invention relates to a method for improving deformation coordination capacity in a 40Cr / Q345B stretching process, which belongs to the technical field of bimetallic component manufacturing, and is characterized by comprising the following steps of: 1) before stretching deformation, taking a bimetallic material to be stretched as a thin plate material, taking a bimetallic ring piece formed by a hot rolling process, arranging 40Cr steel on one side of the thin plate material, and arranging Q345B steel on the other side of the thin plate material; 2) firstly heating the sheet material to a to-be-stretched temperature T on a Gleeble-3500 thermal simulation testing machine, setting a slow stretching rate as v1 and an reached deformation amount as epsilon 1, and then increasing the stretching rate to v2 and an reached deformation amount as epsilon 2; and 3) determining mathematical models of the deformation amounts epsilon 1 and epsilon 2 of the two layers of materials, the stretching temperature and the stretching speed, and obtaining the deformation amount of coordinated deformation of the two layers of materials. The method has the advantages that the coordinated deformation amount of the two materials can be rapidly designed, the coordinated deformation capacity of the bimetallic material is improved, and the design efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of bimetal component manufacturing, and in particular relates to a method for improving the coordinated deformation capability of 40Cr / Q345B during the stretching process. Background Art

[0002] With the rapid development of aerospace, petrochemical, wind power, nuclear power and other industries, the performance requirements for ring parts are getting higher and higher. Single metal rings are increasingly difficult to meet the actual use requirements in terms of performance. Bimetallic rings can combine the advantages of two metal materials at the same time, maximize the complementary advantages of materials, and improve the performance, service life and reliability of parts.

[0003] The traditional manufacturing method of bimetallic rings is time-consuming and labor-intensive, and the bonding effect is not good. A new short-process manufacturing process for bimetallic rings uses bimetallic rings obtained by centrifugal casting to be directly hot-rolled and formed. It has high production efficiency and makes the metals on both sides and the bonding layer have better performance. However, due to the essential differences in the physical and mechanical properties of the metals on both sides, the deformation capacity of bimetallic rings during service is different. For example, if the coordinated deformation capacity of the metals on both sides under tensile loads is improved, so that the bimetallic material can undergo uniform plastic deformation, it will become the focus of bimetallic material research. At present, there is no unified standard to measure the coordinated deformation capacity of bimetallic materials. Summary of the invention

[0004] A method for improving the coordinated deformation ability of 40Cr / Q345B during the stretching process can effectively overcome the shortcomings of the prior art.

[0005] The object of the present invention is achieved by comprising the following steps:

[0006] (1) Before stretching, the bimetallic material to be stretched is a thin sheet. A bimetallic ring formed by hot rolling is obtained. Along the length direction of the bimetallic thin sheet, one side is 40Cr steel and the other side is Q345B steel. The geometric dimensions of the bimetallic thin sheet are set as follows: length L, thickness H, clamping end width B0, clamping end length L 01 , Gauge width B 01 , gauge length is L 01 , the arc transition radius r0 between the clamping end and the gauge length, and the diameter d of the circular hole at the clamping end;

[0007] (2) The tensile test was carried out on a Gleeble-3500 thermal simulation test machine. The in-situ tensile method was used to monitor the tensile deformation during the tensile process. First, the thin sheet was heated to the tensile temperature T, and the slow tensile rate was set to v1, so that the soft phase Q345B steel first underwent plastic deformation. It was constrained by the hard phase 40Cr steel, and the deformation degree was limited, and the deformation reached was ε1. Then the tensile rate was increased to v2, so that 40Cr underwent plastic deformation, and the deformation reached was ε2, which was higher than that of Q345B steel. Under the tensile action, the two steels deformed and necked together until they were fractured.

[0008] (3) Determine the mathematical model of the deformation of the two layers of material ε1, ε2 and the stretching temperature T, stretching speed v1 and v2, and obtain the deformation of the coordinated deformation of the two layers, that is:

[0009] ε 1 = 1 2 [ 0 . 0473 × ex ( T 147 . 70663 ) + 16 . 71388 × ex ( v 1 0 . 88624 ) + 2 . 01584 ] (1)

[0010] ε 2 = 1 2 [ 0 . 05215 × ex ( T 149 . 45221 ) + 11 . 5836 × ex ( v 2 0 . 84824 ) + 26 . 23825 ] (2)

[0011] According to step (3), a method for improving the coordinated deformation ability of 40Cr / Q345B during the stretching process is characterized in that the deformation amount can also be obtained from the following table:

[0012] Relationship table between deformation and stretching process parameters

[0013]

[0014] Advantages and positive effects of the present invention: Since the present invention determines the relationship between the deformation ε1 of Q345B steel and the deformation ε2 of 40Cr steel and the stretching rate and the stretching temperature, when the deformation of 40Cr steel and Q345B steel differs little, it indicates that the coordination deformation ability in the stretching process is strong and the material performance is good. For a bimetallic sheet material formed by a hot rolling process of a certain size, the deformation of the materials on both sides under different stretching temperatures and stretching rates can be simply, quickly and accurately calculated, and the coordination deformation ability in the stretching process can be improved by controlling the process parameters. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is the geometric dimension identification diagram of the tensile specimen;

[0016] Figure 2 It is a schematic diagram of sampling of tensile specimens on bimetallic rings;

[0017] In the figure: L—length, H—thickness, B0—clamping end width, L 01 —Clamping end length, B 01 —Gauge width, L02 —gauge length, r0—arc transition radius between the clamping end and the gauge part, d—diameter of the circular hole at the clamping end. DETAILED DESCRIPTION

[0018] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0019] Figure 1 and Figure 2 They are respectively the geometric dimension identification diagram of the tensile specimen and the sampling schematic diagram of the tensile specimen on the bimetallic ring.

[0020] Example 1

[0021] This embodiment sets a bimetallic ring formed by a hot rolling process: the inner layer is Q345B steel, the outer layer material is 40Cr steel, and the ring size after rolling is 630 mm in outer diameter, 550 mm in inner diameter, and 90 mm in height. A method for improving the coordinated deformation ability of 40Cr / Q345B during stretching is mainly achieved by the following steps:

[0022] (1) Before tensile deformation, the bimetallic material to be stretched is a thin sheet. A bimetallic ring formed by hot rolling process is obtained. Along the length direction of the bimetallic thin sheet, one side is 40Cr steel and the other side is Q345B steel. The geometric dimensions of the bimetallic thin sheet are set as follows: length 20 mm, thickness 5 mm, clamping end width 6 mm, clamping end length 4 mm, gauge width 2 mm, gauge length 8 mm, arc transition radius between the clamping end and the gauge part 2 mm, and clamping end circular hole diameter 6 mm;

[0023] (2) The tensile test was carried out on a Gleeble-3500 thermal simulation test machine. The in-situ tensile method was used to monitor the tensile deformation during the tensile process. First, the thin sheet was heated to the tensile temperature of 900 °C, and the slow tensile rate was set to 0.2 mm / s, so that the soft phase Q345B steel first underwent plastic deformation. It was constrained by the hard phase 40Cr steel, and the deformation degree was limited, reaching a deformation of ε1. Then the tensile rate was increased to 0.3 mm / s, so that 40Cr underwent plastic deformation, reaching a deformation of ε2, which was higher than that of Q345B steel. The two steels deformed and necked together under the tensile action until they were fractured.

[0024] (3) Determine the mathematical model of the deformation of the two layers of material ε1, ε2 and the stretching temperature of 900 °C, the stretching speed of 0.2 mm / s and 0.3 mm / s, and obtain the deformation of the coordinated deformation of the two layers, that is:

[0025] ε 1 = 1 2 [ 0 . 0473 × ex ( 900 147 . 70663 ) + 16 . 71388 × ex ( 0 . 2 0 . 88624 ) + 2 . 01584 ] = 21 . 95 %

[0026] ε 2 = 1 2 [ 0 . 05215 × ex ( 900 149 . 45221 ) + 11 . 5836 × ex ( 0 . 3 0 . 84824 ) + 26 . 23825 ] = 32 . 12 %

[0027] Example 2

[0028] This embodiment sets a bimetallic ring formed by a hot rolling process: the inner layer is Q345B steel, the outer layer material is 40Cr steel, and the ring size after rolling is 630 mm in outer diameter, 550 mm in inner diameter, and 90 mm in height. A method for improving the coordinated deformation ability of 40Cr / Q345B during stretching is mainly achieved by the following steps:

[0029] (1) Before tensile deformation, the bimetallic material to be stretched is a thin sheet. A bimetallic ring formed by hot rolling process is obtained. Along the length direction of the bimetallic thin sheet, one side is 40Cr steel and the other side is Q345B steel. The geometric dimensions of the bimetallic thin sheet are set as follows: length 20 mm, thickness 5 mm, clamping end width 6 mm, clamping end length 4 mm, gauge width 2 mm, gauge length 8 mm, arc transition radius between the clamping end and the gauge part 2 mm, and clamping end circular hole diameter 6 mm;

[0030] (2) The tensile test was carried out on a Gleeble-3500 thermal simulation test machine. The in-situ tensile method was used to monitor the tensile deformation during the tensile process. First, the thin sheet was heated to the tensile temperature of 1050 °C, and the slow tensile rate was set to 1.1 mm / s, so that the soft phase Q345B steel first underwent plastic deformation. It was constrained by the hard phase 40Cr steel, and the deformation degree was limited, reaching a deformation of ε1. Then the tensile rate was increased to 1.3 mm / s, so that 40Cr underwent plastic deformation, reaching a deformation of ε2, which was higher than that of Q345B steel. The two steels deformed and necked together under the tensile action until they were fractured.

[0031] (3) Determine the mathematical model of the deformation of the two layers of material ε1, ε2 and the stretching temperature of 1050 °C, the stretching speed of 1.1 mm / s and 1.3 mm / s, and obtain the deformation of the coordinated deformation of the two layers, that is:

[0032] ε 1 = 1 2 [ 0 . 0473 × ex ( 1050 147 . 70663 ) + 16 . 71388 × ex ( 1 . 1 0 . 88624 ) + 2 . 01584 ] = 58 . 83 %

[0033] ε 2 = 1 2 [ 0 . 05215 × ex ( 1050 149 . 45221 ) + 11 . 5836 × ex ( 1 . 3 0 . 84824 ) + 26 . 23825 ] = 69 . 27 %

[0034] Example 3

[0035] This embodiment sets a bimetallic ring formed by a hot rolling process: the inner layer is Q345B steel, the outer layer material is 40Cr steel, and the ring size after rolling is 630 mm in outer diameter, 550 mm in inner diameter, and 90 mm in height. A method for improving the coordinated deformation ability of 40Cr / Q345B during stretching is mainly achieved by the following steps:

[0036] (1) Before tensile deformation, the bimetallic material to be stretched is a thin sheet. A bimetallic ring formed by hot rolling process is obtained. Along the length direction of the bimetallic thin sheet, one side is 40Cr steel and the other side is Q345B steel. The geometric dimensions of the bimetallic thin sheet are set as follows: length 20 mm, thickness 5 mm, clamping end width 6 mm, clamping end length 4 mm, gauge width 2 mm, gauge length 8 mm, arc transition radius between the clamping end and the gauge part 2 mm, and clamping end circular hole diameter 6 mm;

[0037] (2) The tensile test was carried out on a Gleeble-3500 thermal simulation test machine. The in-situ tensile method was used to monitor the tensile deformation during the tensile process. First, the thin sheet was heated to the tensile temperature of 1200 °C, and the slow tensile rate was set to 2 mm / s, so that the soft phase Q345B steel first underwent plastic deformation. It was constrained by the hard phase 40Cr steel, and the deformation degree was limited, reaching a deformation of ε1. Then the tensile rate was increased to 2.2 mm / s, so that 40Cr underwent plastic deformation, reaching a deformation of ε2, which was higher than that of Q345B steel. The two steels deformed and necked together under the tensile action until they were fractured.

[0038] (3) Determine the mathematical model of the deformation of the two layers of material ε1, ε2 and the stretching temperature of 1200 °C, the stretching speed of 2 mm / s and 2.2 mm / s, and obtain the deformation of the coordinated deformation of the two layers, that is:

[0039] ε 1 = 1 2 [ 0 . 0473 × ex ( 1200 147 . 70663 ) + 16 . 71388 × ex ( 2 0 . 88624 ) + 2 . 01584 ] = 160 . 66 %

[0040] ε 2 = 1 2 [ 0 . 05215 × ex ( 1200 149 . 45221 ) + 11 . 5836 × ex ( 2 . 2 0 . 84824 ) + 26 . 23825 ] = 170 . 64 % .

Claims

1. A method for improving the coordination deformation ability of 40Cr / Q345B during the stretching process, characterized in that Follow these steps to achieve this: (1) Before stretching, the bimetallic material to be stretched is a thin sheet. A bimetallic ring formed by hot rolling is obtained. Along the length direction of the bimetallic thin sheet, one side is 40Cr steel and the other side is Q345B steel. The geometric dimensions of the bimetallic thin sheet are set as follows: length L, thickness H, clamping end width B0, clamping end length L 01 , Gauge width B 01 , gauge length is L 01 , the arc transition radius r0 between the clamping end and the gauge length, and the diameter d of the circular hole at the clamping end; (2) The tensile test was carried out on a Gleeble-3500 thermal simulation test machine. The in-situ tensile method was used to monitor the tensile deformation during the tensile process. First, the thin sheet was heated to the tensile temperature T, and the slow tensile rate was set to v1, so that the soft phase Q345B steel first underwent plastic deformation. It was constrained by the hard phase 40Cr steel, and the deformation degree was limited, and the deformation reached was ε1. Then the tensile rate was increased to v2, so that 40Cr underwent plastic deformation, and the deformation reached was ε2, which was higher than that of Q345B steel. Under the tensile action, the two steels deformed and necked together until they were fractured. (3) Determine the mathematical model of the deformation of the two layers of material ε1, ε2 and the stretching temperature T, stretching speed v1 and v2, and obtain the deformation of the coordinated deformation of the two layers, that is: （1） （2）。 2. A method for improving the coordinated deformation ability of 40Cr / Q345B during the stretching process according to claim 1, characterized in that: The deformation can also be found from the following table: Relationship table between deformation and stretching process parameters 。

Images