發(fā)布時(shí)間：2019-01-05 08:55

【摘要】：焊接是奧氏體不銹鋼板及型材的重要加工手段。高氮奧氏體不銹鋼是用氮部分或完全取代鎳以獲得單相奧氏體組織的一類鋼,可節(jié)約大量鎳,降低成本,且具有優(yōu)良的力學(xué)性能和耐腐蝕性能,因此獲得了廣泛的應(yīng)用。但研究表明,高氮奧氏體不銹鋼在焊接過程中可能會(huì)出現(xiàn)氮的損失、氮化物析出等問題,對(duì)接頭的力學(xué)性能有不利影響。因此,對(duì)高氮奧氏體不銹鋼焊接性能的研究具有實(shí)際意義。本論文使用Gleeble-3500型熱/力模擬試驗(yàn)機(jī)對(duì)固溶處理后的一種新型高氮高錳低鎳奧氏體不銹鋼分別進(jìn)行了峰值溫度為1050℃~1300℃、線能量為5~12kJ/cm條件下的焊接熱影響區(qū)(HAZ)模擬實(shí)驗(yàn),并根據(jù)熱模擬實(shí)驗(yàn)結(jié)果進(jìn)行實(shí)際焊接;采用金相顯微鏡對(duì)模擬HAZ顯微組織和焊接接頭進(jìn)行了分析,結(jié)合使用X射線.衍射、掃描電鏡和透射電鏡對(duì)模擬焊接HAZ顯微組織進(jìn)一步分析,并對(duì)熱模擬實(shí)驗(yàn)鋼和焊接接頭進(jìn)行拉伸、沖擊和硬度測(cè)試,研究實(shí)驗(yàn)鋼模擬焊接HAZ和實(shí)際焊接接頭的力學(xué)性能。研究結(jié)果表明:不同峰值溫度的熱模擬實(shí)驗(yàn)后,實(shí)驗(yàn)鋼晶粒隨峰值溫度的升高逐漸變大;抗拉強(qiáng)度、硬度隨峰值溫度升高逐漸降低,但均分別高于母材799MPa的抗拉強(qiáng)度及其硬度239.26HV;塑性略微低于母材,峰值溫度對(duì)其影響不大;但在峰值溫度為1150℃處呈現(xiàn)不一樣的變化規(guī)律。實(shí)驗(yàn)鋼在經(jīng)歷不同線能量的焊接熱循環(huán)后,焊接HAZ組織主要為奧氏體和孿晶,晶粒中有(Cr,Mn,Fe)23C6析出,隨著線能量的增加,此碳化物析出逐漸消失,晶粒也發(fā)生不同程度的長(zhǎng)大;實(shí)驗(yàn)鋼的塑性略低于母材,但線能量的變化對(duì)其塑性影響不大;實(shí)驗(yàn)鋼硬度均高于母材,不存在軟化區(qū)域;線能量為10kJ/cm時(shí),實(shí)驗(yàn)鋼具有最佳的力學(xué)性能,抗拉強(qiáng)度達(dá)到826MPa,延伸率54.6%,吸收功306.1J,硬度為319.03HV。采用優(yōu)化后的試驗(yàn)參數(shù)對(duì)實(shí)驗(yàn)鋼進(jìn)行了TIG焊,焊接接頭熱影響區(qū)組織均勻,硬度高于母材,拉伸斷口出現(xiàn)在焊縫上。
[Abstract]:Welding is an important means of processing austenitic stainless steel plates and profiles. High nitrogen austenitic stainless steel is a kind of steel which uses nitrogen partly or completely to replace nickel to obtain single-phase austenitic structure. It can save a lot of nickel, reduce cost, and has excellent mechanical properties and corrosion resistance, so it has been widely used. However, the study shows that the loss of nitrogen and the precipitation of nitride may occur in the welding process of high nitrogen austenitic stainless steel, which has a negative effect on the mechanical properties of the joints. Therefore, it is of practical significance to study the welding properties of high nitrogen austenitic stainless steel. In this paper, a new type of high nitrogen, high manganese and low nickel austenitic stainless steel after solid solution treatment was studied by using Gleeble-3500 thermal / mechanical simulator. The peak temperature of the austenitic stainless steel was 1050 鈩，

本文編號(hào)：2401548