Diffusible hydrogen management in underwater wet self-shielded flux cored arc welding

This article reports the effect of underwater wet welding parameters and conditions on the diffusible hydrogen content in deposited metal for welding with a self-shielded flux cored wire. The diffusible hydrogen content in deposited metal was determined using the glycerin method according to the Plackett-Burman design determining the significance of the effect of the stick out length, welding current, arc voltage, travel speed and water salinity. The results of the measurements of the diffusible hydrogen content in deposited metal ranged from 25.85 to 44.12 ml/100 g. The effect of all the tested factors is statistically significant. An equation was also developed, the analysis of which showed, that the hydrogen content cannot be reduced by technological methods below 21 ml/100 g.     

液压支架中低合金调质高强钢的焊接

通过对高强钢焊接性影响因素的分析,论述了如何合理选择焊接工艺.     

Measuring laser weldability of aluminium alloys using controlled restraint weldability test

Abstract

Al–Mg–Si alloys are known to be highly susceptible to solidification cracking. Weldability results of laminated AA6061-T6 plates are presented in this paper when welded in full penetration keyhole mode using a 1030 nm, 10 kW Yb:YAG disk laser welding source with different welding conditions. Making use of the controlled restraint weldability (CRW) cracking test, a boundary has been established between crack and no crack conditions for different preloads. The originality of the CRW test is the cross-shaped test coupon that partitions the pre-stress unequally along the welding path. The CRW is proven capable of ranking the solidification cracking behaviour of weld metals deposited under different welding conditions.     

Effect of solution heat treatments on superalloys Part 1 – alloy 718

Abstract

The hot ductility as measured by Gleeble testing of Alloy 718 at four different solution heat treatments (954°C/15 h, 954°C/1 h, 982°C/1 h and 1050°C/3 h+954°C/1 h) has been investigated. It is concluded that constitutional liquation of NbC assisted by δ phase takes place and deteriorates the ductility. Parameters established by analysing the ductility dependence on temperature indicate a reduced weldability of the material in the coarse grain size state (ASTM 3) while indicating an increased weldability when containing a large amount of δ phase due to a grain boundary pinning effect. The accumulation of trace elements during grain growth at the highest temperature is believed to be the cause for the observed reduced on-cooling ductility.     

HQ 100钢焊接性研究

本文研究了HQ 100钢模拟及实际焊接热影响区各部位的韧性及组织变化,并用插销试验、纵向可调拘束裂纹试验和T型坡口再热裂纹试验对HQ 100钢的裂纹敏感性进行了评定。试验结果表明,模拟热循环峰值温度对HQ 100热影响区韧性有明显影响。随峰值温度升高,冲击韧性下降。Δt 8/5对韧性也有一定影响,当Δt 8/5为10 s时,过热区韧性最佳。实际热影响区峰值温度对韧性的影响也具有同样的规律性,但其韧性比模拟热影响区高一倍左右。组织和晶粒度的不同是造成上述变化的重要原因。抗裂性试验结果表明,HQ 100钢具有良好的抗热裂纹,再热裂纹性能。冷裂敏感性也较低,只要严格控制焊条烘干条件,预热和层温不低于130℃,便不会产生冷裂纹。     

两种不同焊丝对7A05铝合金焊接性的影响

选择两种焊丝,对Al Zn Mg系合金7A05 T6进行焊接性研究。焊接裂纹试验结果表明,采用两种焊丝焊接7A05合金时,接头均具有较好的抗热裂纹敏感性。两种焊丝焊接接头的拉伸强度均为母材强度的75%以上,经过时效处理的焊接接头力学性能有了明显的提高。分析认为微观组织中沉淀物质点越小,均匀分散到晶界上越多,接头的拉伸强度越高。     

新一代高强韧性WDL系列钢综合性能及应用

本文着重介绍武汉钢铁公司近年来研制开发的第二代高强度低合金钢—高强韧性WDL系列钢的综合性能及应用情况。该钢具有优异的焊接性能和低温韧性,板厚≤50mm钢板焊前不预热或稍加预热而不产生焊接裂纹,是制造大型压力容器（特别是低温和常温球罐）、水电站压力钢管和水轮机蜗壳、高寒地区使用的大型工程机械、大跨度桥梁及海上采油平台等装备的理想用材。     

AVESTA2205焊接性研究及生产应用

对AVESTA2205的可焊性进行分析,了解各种因素对焊接接头的影响,焊接接头在焊后的组织与力学性能,最后制定合理的焊接工艺,保证焊缝质量,达到设计要求。     

TA2/316L的连接技术及其腐蚀与防护

钛钢复合板既可以充分发挥基材各自的优点,也是节约贵金属最好的途径,在舰船上应用有明显的社会效益和经济效益,值得进一步应用推广。爆炸焊接、轧制复合、摩擦焊和扩散焊是目前主要的层状金属复合板的生产方法,其中,爆炸复合法在生产中应用最为广泛。本文通过分析TA2与316L的焊接性,对其连接方法和主要应用领域进行综述,概述了TA2/316L在海水介质中的主要腐蚀类型及防护方法。