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Steel for bearing ring of large-size shield tunneling machine and heat treatment method thereof

A heat treatment method and technology for bearing rings, which are applied in the field of alloy structural steel, can solve the problems of unreported steel with performance, and achieve the effects of increasing the allowable cooling rate range, improving hardenability, and widening the process window.

Inactive Publication Date: 2015-04-22
UNIV OF SCI & TECH BEIJING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, there is no report on the steel used to meet the performance of large-size shield machine bearing rings

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] A steel for large-size shield machine bearing rings, which is composed of the following elements and contents (by weight percentage):

[0020] C: 0.41, Si: 0.17, Mn: 0.60, Cr: 0.90, Mo: 0.15, Ni: 0.50, P: ≤0.015, S: ≤0.003, H: ≤0.00018, O: ≤0.0015, the rest is Fe and normal of impurities. The end quenching experiment was used to test the depth of the hardened layer of the material, and the results are shown in Table 1.

[0021] Step 1: Heat the material until fully austenitized, the austenitized heating temperature is 925°C, the holding time is 2.0min / mm, and then put the material into oil and cool to room temperature.

[0022] Step 2: The material treated in step 1 is then subjected to high-temperature tempering treatment at a heating temperature of 650°C and a holding time of 3 hours, and then the material is cooled to room temperature in air. The impact toughness and hardness (HB) of the processed material were tested, and the results are shown in Table 1.

[0023...

Embodiment 2

[0025] A steel for large-size shield machine bearing rings, which is composed of the following elements and contents (by weight percentage):

[0026] C: 0.43, Si: 0.25, Mn: 0.75, Cr: 0.95, Mo: 0.18, Ni: 0.59, P: ≤0.015, S: ≤0.003, H: ≤0.00018, O: ≤0.0015, the rest is Fe and normal of impurities. The end quenching experiment was used to test the depth of the hardened layer of the material, and the results are shown in Table 1.

[0027] Step 1: Heat the material until fully austenitized, the austenitized heating temperature is 925°C, the holding time is 2.0min / mm, and then put the material into oil and cool to room temperature.

[0028] Step 2: The material treated in step 1 is then subjected to high-temperature tempering treatment at a heating temperature of 650°C and a holding time of 3 hours, and then the material is cooled to room temperature in air. The impact toughness and hardness (HB) of the processed material were tested, and the results are shown in Table 1.

[0029...

Embodiment 3

[0031] A steel for large-size shield machine bearing rings, which is composed of the following elements and contents (by weight percentage):

[0032] C: 0.42, Si: 0.20, Mn: 0.65, Cr: 1.00, Mo: 0.205, Ni: 0.55, P: ≤0.015, S: ≤0.003, H: ≤0.00018, O: ≤0.0015, the rest is Fe and normal of impurities. The end quenching experiment was used to test the depth of the hardened layer of the material, and the results are shown in Table 1.

[0033] Step 1: Heat the material until fully austenitized, the austenitized heating temperature is 925°C, the holding time is 2.0min / mm, and then put the material into oil and cool to room temperature.

[0034] Step 2: The material treated in step 1 is then subjected to high-temperature tempering treatment at a heating temperature of 650°C and a holding time of 3 hours, and then the material is cooled to room temperature in air. The impact toughness and hardness (HB) of the processed material were tested, and the results are shown in Table 1.

[003...

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PUM

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Abstract

The invention discloses steel for a bearing ring of a large-size shield tunneling machine and a heat treatment method thereof. The steel consists of the following elements in percentage by weight: 0.41-0.45 percent of C, 0.17-0.37 percent of Si, 0.60-0.80 percent of Mn, 0.90-1.20 percent of Cr, 0.15-0.25 percent of Mo, 0.50-0.70 percent of Ni, less than or equal to 0.015 percent of P, less than or equal to 0.003 percent of S, less than or equal to 0.00018 percent of H, less than or equal to 0.0015 percent of O and the balance of Fe and normal impurities. The experiment steel subjected to alloying design has good hardenability, the hardening layer depth can be over 40mm in the end quenching experiment and is 30mm higher than that of 42CrMo; the bearing ring of the large-size shield tunneling machine is wholly subjected to quenched-tempered heat treatment, and after the surface is subjected to induction hardening, the surface hardening layer texture is cryptocrystalline martensite, and the matrix structure is tempered sorbite; the surface has high hardness and has the average value of 58.5-60.3HRC; the core has good toughness, the impact toughness AKv value at the temperature of 20 DEG C below zero is over 106J; and the steel has proper hardness, and the average value of the hardness is 272-283HB. Meanwhile, a control process window of an actual production cooling medium is wide, and the cooling speed is over 10 DEG C per second. Therefore, the requirement on the comprehensive mechanical property of the steel for the bearing ring of the large-size shield tunneling machine can be met.

Description

technical field [0001] The invention relates to an alloy structural steel, which belongs to the alloy type (C22C), and is suitable for steel for bearing rings of large-size shield machine with high comprehensive mechanical performance requirements and a heat treatment method thereof. Background technique [0002] With the rapid development of urban construction, a large number of traffic tunnels, urban underground railways, water supply and drainage tunnels and cable tunnels have been built, under repair or are being planned. As the main construction machine for shield construction, the shield machine is currently showing a trend of large-diameter development. The Chongming Tunnel in Shanghai has begun to use a shield machine with a diameter of 15m. As the main component of the shield machine bearing, the bearing ring of the shield machine needs to reach a size of 6m or more. Therefore, on the basis of high fatigue strength, hardness, compressive strength, elastic limit, we...

Claims

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Application Information

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IPC IPC(8): C22C38/44C21D6/00
Inventor 刘雅政蒋波董正强周乐育张朝磊文新理
Owner UNIV OF SCI & TECH BEIJING
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