發(fā)布時(shí)間：2018-06-07 07:41

  本文選題：制動(dòng)輪 + 裂紋��； 參考：《大連理工大學(xué)》2014年碩士論文

【摘要】：制動(dòng)輪是起重機(jī)類(lèi)產(chǎn)品的重要零部件。大噸位起重機(jī)服役一段時(shí)間后,常會(huì)在制動(dòng)輪表面出現(xiàn)裂紋,裂紋的出現(xiàn)會(huì)導(dǎo)致制動(dòng)輪的破壞,使起重機(jī)產(chǎn)生安全隱患。研究新型起重機(jī)制動(dòng)輪材料的組織性能及制動(dòng)輪表面應(yīng)力狀態(tài),對(duì)分析制動(dòng)輪表面裂紋缺陷的產(chǎn)生,有效提高制動(dòng)輪的使用壽命具有重要的意義。 本文以研制新型高性能起重機(jī)用制動(dòng)輪為目標(biāo),主要開(kāi)展了三方面的研究?jī)?nèi)容：1.在原制動(dòng)輪材料的基礎(chǔ)上,通過(guò)添加合金元素,提高材料的熱疲勞性能和綜合力學(xué)性能指標(biāo)；2.通過(guò)三種新型合金試樣在不同熱處理工藝條件下的金相組織和力學(xué)性能分析,初步確定新型制動(dòng)輪合金的化學(xué)成份和熱處理工藝；3.通過(guò)制動(dòng)輪表面殘余應(yīng)力的測(cè)試,分析和探討殘余應(yīng)力對(duì)制動(dòng)輪表面發(fā)生裂紋缺陷的影響。研究結(jié)果表明： 對(duì)于ZG340A、ZG340B和ZG35CrMnSi,通過(guò)優(yōu)化熱處理工藝可以得到滿(mǎn)足制動(dòng)輪服役要求的使用性能。由于ZG340A和ZG35CrMnSi合金均具有良好的綜合使用性能,應(yīng)優(yōu)先考慮選擇。這兩種合金比較合理的熱處理工藝分別為ZG340A:870℃正火+550℃回火；ZG35CrMnSi:860℃淬火+600℃回火。 ZG340A合金(正火十回火)具有良好的綜合性能,降低了其對(duì)表面缺陷、夾雜以及氧化物等潛在疲勞裂紋源的敏感性,同時(shí)其微觀組織特性有利于緩解裂紋尖端處的應(yīng)力集中,阻止疲勞裂紋的擴(kuò)展；ZG340A合金在高溫下(500℃)的磨損表面沒(méi)有發(fā)生嚴(yán)重的氧化現(xiàn)象,由于遷移的Ni、r等元素以氧化物的形式殘留在磨損表面,使磨損很快進(jìn)入穩(wěn)態(tài)階段；ZG340A合金的基體,易于形成磨屑遷移,而遷移磨屑滯留在磨損表面,起到一定的承載和穩(wěn)定磨損的作用,因此具有較好的抗磨損性能。 35CrMnSi合金具有較高的斷裂韌性和高溫強(qiáng)度,其磨損機(jī)制主要為顯微剝落。其高溫磨損的顯微剝落呈現(xiàn)比較均勻的狀態(tài),幾乎沒(méi)有出現(xiàn)局部的宏觀剝落深坑,35CrMnSi合金也同樣具有良好的抗磨損性能。 制動(dòng)輪表面殘余應(yīng)力不大,實(shí)測(cè)的最大應(yīng)力值小于62.2MPa,而且分布比較均勻。在進(jìn)行粗加工和精加工后,表面殘余應(yīng)力還會(huì)進(jìn)一步降低；制動(dòng)輪服役時(shí),由于表面的反復(fù)擠壓,而使表面應(yīng)力得到進(jìn)一步釋放,殘余應(yīng)力會(huì)降到更低值。因此,殘余應(yīng)力對(duì)制動(dòng)輪服役時(shí)表面裂紋的產(chǎn)生不會(huì)起主要的作用,合金成分、冶金質(zhì)量、熱處理工藝和服役時(shí)周期變化的接觸力作用是導(dǎo)致制動(dòng)輪表面產(chǎn)生裂紋的主要原因。
[Abstract]:Brake wheel is an important part of crane products. After the large tonnage crane has been in service for a period of time, cracks often appear on the surface of the brake wheel, which will lead to the failure of the brake wheel and make the crane have a hidden danger of safety. The study of the structure and properties of the brake wheel material and the stress state on the surface of the brake wheel is of great significance to the analysis of the surface crack defects of the brake wheel and the effective improvement of the service life of the brake wheel. Aiming at the development of a new type of brake wheel for high performance crane, this paper mainly develops three aspects of research contents: 1. On the basis of the original brake wheel material, the thermal fatigue properties and the comprehensive mechanical properties of the material were improved by adding alloying elements. Based on the analysis of metallographic structure and mechanical properties of three new alloy samples under different heat treatment conditions, the chemical composition and heat treatment process of the new type brake wheel alloy are preliminarily determined. By measuring the residual stress on the surface of the brake wheel, the influence of the residual stress on the crack on the surface of the brake wheel is analyzed and discussed. The results show that: For ZG340A, ZG340B and ZG35CrMnSi, the service performance of brake wheel can be obtained by optimizing heat treatment process. As both ZG340A and ZG35CrMnSi alloys have good comprehensive performance, preference should be given to their selection. The reasonable heat treatment process of the two alloys is ZG340A:870 鈩，

本文編號(hào)：1990390