焊后热处理对31CrMoV9钢电子束焊接接头组织及性能的影响

研究了31CrMoV9钢电子束焊接接头在焊后去应力退火、焊后调质两种不同焊后热处理状态下的焊缝组织与性能,并与同等强度等级下的母材组织与性能进行了对比研究。结果表明,接头焊后组织为板条马氏体及少量残留奥氏体;焊缝经调质处理后,组织为相对均匀的回火索氏体,接头力学性能与母材相当,相比于焊后去应力退火处理,焊缝冲击性能大幅提高。两种类型的焊后热处理均未消除焊缝柱状枝晶等凝固组织形态,但焊后调质工艺可减轻焊缝柱状枝晶组织偏析,并使之细化,使得焊缝与母材的组织与硬度更加均匀;焊后经多次重复淬火,焊缝经检测均未见裂纹,说明焊后采用调质工艺可行,这为提高焊缝冲击性能提供了可行工艺路线。     

Influence of pre- and post-weld heating on weldability of modified 9Cr–1Mo(V–Nb) steel pipe under shielded metal arc and tungsten inert gas welding processes

Abstract

Welding of modified 9Cr–1Mo(V–Nb) steel pipes has been carried out via shielded metal arc (SMA) and tungsten inert gas (TIG) welding processes. The weld joints have been produced using different preheating temperatures, followed by post-weld heat treatment (PWHT) at various temperatures. The microstructures of the weld and of the heat affected zone (HAZ) of the weld joints have been studied under the optical microscope and correlated with the preheating and PWHT. The average hardness of the weld and different regions of the HAZ, and tensile properties of the weld joints have also been studied and correlated with the preheating and PWHT. The tensile properties of the SMA and TIG weld joints produced using preheating and PWHT at various temperatures are compared and correlated with their microstructures. It is noted that a comparatively high preheating temperature of the order of 573 K is beneficial, and PWHT is necessary to reduce the susceptibility to cold cracking of weld joints of the present steel. The PWHT at 1123 K enhances ductility to fracture, but decreases the tensile strength of the base material, causing fracture of both the SMA and TIG weld joints from this region close to the HAZ. The tensile properties of SMA welds are found to be superior to those of the TIG welds, especially for PWHT at temperatures up to 1023 K.     

新型贝氏体装甲钢的组织和力学性能

研究了高强度新型贝氏体装甲钢板热轧、低温回火和热轧、正火、低温回火及不同温度回火的组织和性能,测试了不同低温的冲击韧度和焊接接头的力学性能.结果表明,轧态、低温回火和正火低温回火钢板的组织为贝氏体铁素体和残余奥氏体组织,淬火低温回火钢板的组织为马氏体、贝氏体铁素体和残余奥氏体组织.不同状态的装甲钢板具有高的回火抗力、良好的强韧性及低温冲击韧度和焊接性能,及可作为车辆防护装甲.     

热处理工艺对0Cr13Ni5Mo钢焊接接头组织和性能的影响

对马氏体不锈钢0Cr13Ni5Mo焊接接头经过1000℃油淬后,分别进行了600℃,620℃+600℃,400℃回火。通过显微组织分析、拉伸试验、冲击试验和硬度检测对3种焊接接头的组织和力学性能进行了研究。结果表明,3种焊接接头中焊缝组织粗大,硬度最高;焊接接头的韧性低于相应热处理状态下母材的韧性;随着回火温度的降低,韧性下降,强度提高。二次回火比一次回火组织更加细小,强度和韧性更好;620℃+600℃二次回火后焊接接头具有比较理想的综合力学性能。     

焊后热处理对DQTHT80钢热影响区断裂韧性的影响

研究了直接淬火回火调质钢ＤＱＴＨＴ８０多层焊热影响我的ＣＴＯＤ断裂韧性。焊态和焊后热处理状态下的试验结果表明：焊态下热影响区断裂韧性高于焊后热处理态。焊后热处理降低了该钢热影响区的断裂韧性。焊态下断口韧窝状,而焊后热处理断口叶解理状。模拟焊接热影响区粗晶区试验结果进一步证实了焊后热处理对韧性的不利影响。     

Variation of microstructures and mechanical properties in the post-weld heat-treated HAZ of Cu containing HSLA steel welds

The present study focuses on the effect of Cu and post-weld heat treatment (PWHT) on the microstructure and mechanical properties in the coarse grained heat affected zone (CGHAZ) of Cu containing high strength low alloy (HSLA) steel welds. For this study, HSLA steels with and without Cu were prepared in laboratory. Mechanical properties were estimated by Vickers hardness and Charpy impact tests. As a result, despite PWHT, the Vickers hardness did not change noticeably; however, the impact toughness deteriorated significantly with increasing PWHT time. In case of Cu added steel, intergranular brittle fractures occurred after PWHT, due to the strengthening of the grain interior by precipitation of Cu particles. Additionally, the formation of a soft denuded grain boundary zone also played a significant role in lowering the fracture toughness during PWHT.     

回火温度对Q1100超高强钢组织和性能的影响

采用力学性能测试、显微组织观察、扫描电镜观察,研究回火温度对Q1100超高强钢组织和性能的影响规律。结果表明:试验钢900 ℃保温后水淬再200~300 ℃回火后,为回火板条马氏体组织;在 400 ℃和500 ℃回火后,为回火屈氏体组织;在600 ℃回火后,为回火索氏体组织。试验钢具有较高的回火稳定性,在400~600 ℃回火时,α铁素体仍保持板条马氏体的形状和位向。在200 ℃回火后,小角度晶界含量较多,阻碍微裂纹扩展,韧性较好,随着回火温度的升高,小角度晶界占比逐渐减少,在400 ℃回火后,小角度晶界占比较少,碳化物的析出恶化试验钢的韧性,发生了回火脆性,韧性最差,500 ℃和600 ℃回火后,试验钢的小角度晶界占比较400 ℃相差不明显,但试验钢回复程度较大且600 ℃回火发生部分再结晶,回火软化作用较大,韧性较高。当回火温度为200 ℃时,试验钢具有最佳的综合性能,屈服强度为1164.38 MPa,抗拉强度为1429.70 MPa,断后伸长率为14.66%,硬度为430.27 HV3,标准试样-40 ℃冲击吸收能量为92.30 J。     

回火温度对Q890高强钢组织和性能的影响

研究了回火温度对经一定温度淬火后的Q890高强度钢组织和力学性能的影响。结果表明,从920℃淬火并于200～700℃回火时,随着回火温度的升高,Q890钢的淬火马氏体逐渐转变为回火马氏体、回火托氏体及回火索氏体,硬度总体呈下降趋势;600℃回火后,Q890钢的组织主要为回火托氏体,硬度为35HRC。此外,经从920℃淬火和600℃回火的5～25mm厚Q890钢板的屈服强度均大于900MPa,-40℃的冲击韧度均大于45J。     

26CrMoVNbRE钢高效热处理调质工艺边界探索

研究了不同淬火温度、淬火保温时间、回火温度及回火保温时间对26CrMoVNbRE钢组织与性能的影响,结果表明,试验钢870～900℃淬火后高温回火,显微组织为回火索氏体,原始奥氏体晶粒细小均匀.870℃保温40 min淬火,与900℃保温30 min淬火屈服强度相近,前者有良好的综合力学性能,后者更有利于现场高效热处理...     

低温压力容器用SA537 CL2钢板的开发

为满足市场对低温压力容器用钢板强度高、可焊接性好、抗断裂性能优异、韧性转变温度低且生产成本低的要求,河北普阳钢铁有限公司开发了美标调质型低温压力容器用钢板SA537 CL2.其采用低碳成分设计,并添加Cr合金元素来提高钢板的淬透性;通过生产试验,获得了最佳生产工艺参数,即第1阶段开轧温度不小于1 050℃,终轧温度95...     

Toughness evaluation of a shielded metal arc carbon-manganese steel welded joint subjected to multiple post weld heat treatment

This study was part of a program to investigate the influence of multiple post weld heat treatment (PWHT) on the fracture toughness and defect tolerance of a welded joint. The present work reports base metal data obtained for a quenched and tempered BS7191 Grade 450EM steel (0.10wt%C–1.08wt%Mn), weld metal data for a ferritic multipass weld obtained by shielded metal arc welding using an AWS E9018M type electrode, and heat affected zone (HAZ) data obtained using a modified bead on groove technique for different PWHT conditions. The effect of the repeated heat treatment cycles on the mechanical properties was evaluated by hardness tests and toughness testing assessed by Charpy V-notch and crack tip opening displacement (CTOD) techniques. The characterization of the microstructure was undertaken utilizing optical and electron microscopy. As fabrication codes for new equipment do not allow more than three PWHT cycles, the application of more cycles is only justifiable for old equipment when a fitness for purpose criterion is applied and these restrictions are not applicable. The results obtained are currently applied in repair work and revamps of pressure vessels and gas storage tanks.     

GD钢组织及低温冲击韧性研究

分析了900℃淬火及200℃回火后GD钢的显微组织、硬度及低温冲击的断口形貌,研究结果表明:900℃淬火后GD钢组织由粗针状马氏体、残余奥氏体、碳化物组成,200℃回火时,马氏体中析出部分碳化物,回火组织由回火马氏体和碳化物组成。900℃淬火+200℃回火后的GD钢冲击时,随着温度的降低,其冲击功随之减小,随着GD钢所处的环境温度不断升高,断口宏观形貌中反映起裂区和裂纹纤维扩展区所占比例越来越大,微观形貌中存在解理面、撕裂棱和韧窝,其断裂机理为准解理断裂。     

热处理工艺对G105钻杆材料抗腐蚀性能的影响

通过对G105钻杆材料热处理工艺试验,研究不同回火温度对材料组织的影响,并利用电化学测试和慢应变速率拉伸试验分析G105钻杆材料在不同热处理条件下的组织和性能变化对其腐蚀性能的影响。结果表明：采用890℃淬火+620℃回火、890℃淬火+580℃回火热处理后,材料性能能够满足G105钻杆技术要求;回火温度影响材料的力学性能,回火温度越高材料的塑性及韧性越强;采用890℃淬火+620℃回火处理后的显微组织优于890℃淬火+580℃回火工艺,并具有更佳的抗腐蚀性能。     

机车车体Q345E钢Ar+CO_2+O_2三元混合保护气体MAG焊接头的组织和性能

选用富氩低氧化性的Ar+CO_2+O_2三元混合焊接气体(即Rich-argon Lower-oxidizability Ar+CO_2+O_2三元混合气体,简称RALO三元混合气体),通过与传统φ(Ar)80%+φ(CO_2)20%二元混合焊接气体(简称二元混合气体)相对比,研究机车车体Q345E钢MAG焊接头的组织和性能。试验结果表明,RALO三元混合气体的焊缝成形较为平滑、美观;三元混合气体的焊缝低温冲击韧性略高于二元混合气体,冲击吸收功A_(kv)(-40℃)值高出约13%;选用三元混合气体或二元混合气体进行焊接,MAG焊接头的组织特征上差别不大,即组织类型相同、形貌特征相似、晶粒尺寸相近,且焊接接头塑性良好,静载拉伸试验试样均断裂于远离焊缝的母材处。     

回火温度对3Cr3Mo2NiW钢力学性能和断口形貌的影响

研究了3Cr3Mo2NiW钢力学性能和断口形貌随回火温度的变化。结果显示,随着回火温度的升高,试验钢的硬度降低,韧性增加,550 ℃回火时出现二次硬化现象;600 ℃以上回火,硬度明显降低,韧性大幅度增加;700 ℃回火态试样未冲断。淬火后,随着回火温度的升高,试验钢的基体组织逐渐转变为回火马氏体、回火屈氏体和回火索氏体。300~600 ℃温度区间内回火试样的断裂方式为准解理断裂,高温回火试样的断裂方式为韧性断裂,不同温度回火后得到的显微组织和碳化物对试样的冲击韧性有较大影响。     

Microstructure and fatigue crack growth behaviour of electron beam welding in 30CrMnSiNi2A steel

The effects of two post-weld heat treatment processes on the microstructure and fatigue properties of the electron beam welded joints of 30CrMnSiNi2A steel were studied. Electron beam local post-weld heat treatment ( EBLPWHT) , in a vacuum chamber, immediately after welding and a traditional furnace whole post-weld heat treatment (FWPWHT) were accepted. The experimental results show that, after EBLPWHT, the main microstructure of weld is changed from coarse acicular martensite into lath martensite, and base metal is changed from ferrite and perlite into upper bainite and residual austenite, however the microstructures of different zones of joints in FWPWHT conditions are tempered sorbite. The fatigue crack growth rate da/dN of welds and base metal are not obviously changed among EBLPWHT, FWPWHT test and as-welded (AW) test, as the mechanical properties of materials have a certain but not large effect on the da/dN of welded joints. The resistance to near threshold fatigue crack growth data of welded joints can be largely improved by EBLPWHT and it is related to microstructure and crack closure effect.     

非调质HB400级高强度耐磨钢板焊接接头组织与性能

利用手工电弧焊研究了非调质HB400耐磨板的焊接接头的组织和力学性能,结果表明,焊缝组织主要为块状铁素体和少量珠光体,热影响区组织为新型贝氏体组织,熔合区结合良好,晶粒比较细小,非调质HB400耐磨板焊接接头具有良好的强韧性。     

Microstructure and Mechanical Properties of Laser Welded Joints of DZ125L and IN718 Nickel Base Superalloys

The microstructure and mechanical properties of the laser welded joint of DZ125L and IN718 nickel base superalloys were investigated. The results show that the fusion zone (FZ) mainly consists of fine dendrite structure with fine γ′, Laves phases and MC carbides inhomogeneously distributed. The high welding temperature induces the partial dissolution of γ′ in the heat-affected zone (HAZ) of DZ125L and liquation of grain boundaries in both of the HAZs. After post-weld heat treatment (PWHT), fine γ″ and γ′ phases precipitate in the FZ, IN718 HAZ and IN718 base metal (BM), and fine γ′ precipitate in the γ channel of the HAZ and BM of DZ125L. With tensile testing, the joints after PWHT show higher strengths than that of the weaker DZ125L alloy. Plastic deformation mainly concentrates in the weaker DZ125L and the joint finally fails in the DZ125L BM.     

不同热处理制度下1Cr11Ni2W2MoV闪光对焊接头的组织与性能

针对1Cr11Ni2W2MoV不锈钢开展闪光对焊试验,研究不同焊后热处理制度对其焊接接头组织和力学性能的影响。结果表明:采用闪光对焊方法焊接1Cr11Ni2W2MoV,能够获得优质的焊接接头。1Cr11Ni2W2MoV闪光焊焊态下焊缝组织为马氏体和少量的δ铁素体组织,焊接接头具有较好的拉伸性能,但塑性和韧性较差。经过淬火+回火热处理后组织表现为回火索氏体组织,焊接接头的抗拉强度、塑性和韧性等性能均得到改善。在1000℃油淬+570℃回火状态下,焊接接头具有良好的综合力学性能。     

Effect of groove shapes on mechanical properties of welded joints of ASTM4130 steel

The 30 mm thick ASTM4130 steel pipe was fabricated by gas tungsten arc welding and shielded metal arc welding under quenched and tempered conditions.Whereafier,the mechanical properties of welded joints of both V groove and combination double V groove were measured,while the microstructure feature and fracture morphology of both welded joints were investigated.Moreover,the effect of groove shapes on the properties of welded joints was explored.The results show that the welding efficiency of the combination double V groove joint is as two times as that of the V groove joint.But the hardness and toughness of the heat-affected zone (HAZ) with combination double V groove can not satisfy the requirements.Also,the coarse grain heat-affected zone (CGHAZ) of the cap layer is mainly composed of granular bainite,tempered manensite and a small amount of carbon-free bainite,and the fractured surface of the fusion line is entirely dominated by the quasi-cleavage mode.That the mechanical properties of the combination double V groove are lower than that of the V groove lie in the penetration ratio,welding heat input,and the areas and distribution feature of brittle zones.The combination double V groove is not suitable for the fabricating of ASTM4130 steel.