双相不锈钢带极电渣堆焊材料的研制

研制出了2209型双相不锈钢带极堆焊焊带及配套焊剂,采用该套材料进行了带极堆焊试验,结果表明堆焊后熔敷金属化学成分、力学性能、耐腐蚀性能优良.堆焊金属的铁素体含量在30%～60%,达到了国外同类焊接材料的实物水平.     

2209型双相不锈钢丝极埋弧焊材料的研制

研制开发了2205双相不锈钢焊接用丝极埋弧焊材料,包括SAW2209焊丝及配套烧结焊剂SJ676,改善了目前国内双相不锈钢埋弧焊焊接材料大部分依赖进口的现状.研制的SJ676焊剂,采用CaF2-Al2O3碱性渣系,碱度为2.6,具有良好的焊接工艺性及冶金性能.熔敷金属理化性能与力学性能优异,无晶间腐蚀倾向.焊接接头各区域铁素体含量均在30％～70％范围内,性能满足标准要求.     

新型2205型双相不锈钢埋弧焊用烧结焊剂

开发了焊接2205型双相钢的埋弧焊用烧结焊剂,渣系为CaF2-SiO2-MgO-Al2O3,属于中性焊剂。该焊剂有良好的工艺性能和冶金性能,配合焊丝ER2209焊接所得熔敷金属为铁素体+奥氏体双相结构。熔敷金属有较高的强度和良好的塑性,其中铁素体含量为22%～35%。研究发现室温时效时间和焊道最终温度对熔敷金属中的铁素体含量有影响,随着室温时效的延长和焊缝最终温度的降低,熔敷金属中的铁素体含量增加。     

核电用EQ308L不锈钢带极埋弧堆焊材料的研制

通过对EQ308L不锈钢带极埋弧堆焊材料控氮处理,解决了EQ308L小锈钢带极埋弧堆焊材料室温抗拉强度不能稳定≥520 MPa的难题。当熔敷金属氮含量在0.05%~0.20%时,采用该套材料进行带檄埋弧堆焊试验,堆焊工艺性能极佳,冶金性能优异,熔敷金属力学性能、耐蚀性能优良,满足了核电的要求。     

带极电渣堆焊奥氏体不锈钢耐晶间腐蚀性能

用带极电渣堆焊和带极埋弧堆焊2种方法堆焊了Cr-Ni不锈钢,研究了这两种方法和焊接速度对堆焊层金属显微组织及耐晶间腐蚀性能的影响。显微组织观察表明,带极电渣堆焊和带极埋弧堆焊层的显微组织都为奥氏体+δ铁素体。带极电渣堆焊层金属中δ铁素体随着焊速的提高而增多,含量由6。8%增加到20.4%,带极埋弧堆焊金属中的δ铁素体含量比带极电渣堆焊的高,达到了23.6%;电化学动电位再活化试验结果表明,焊接速度8m/h的带极电渣堆焊层金属的再活化率仅为3.22%,耐晶间腐蚀的性能最佳,焊速快慢或焊接方法改变都将使带极电渣堆焊层金属的再活化率升高,耐晶间腐蚀性能下降。10%草酸溶液电解浸蚀试验的结果与EPR曲线结果一致。     

核电用EQ309L不锈钢带极埋弧堆焊材料的研制

通过合理调整EQ309L熔敷金属的铁素体含量,提高了长时间热处理后熔敷金属的断后伸长率;对EQ309L焊带进行控氮处理,解决了室温抗拉强度不能稳定大于等于520 MPa的难题;通过改变焊剂中碳酸盐、硅酸盐及氟化物的比例改善焊剂工艺性能,解决了表面压痕和粘渣问题.研制出的EQ309L不锈钢带极埋弧堆焊材料WEQ309HR焊带和WSJ309HR烧结焊剂,其各项性能均满足核电设备制造的要求.同时研究了焊接热输入、焊接电流和焊接速度对EQ309L熔敷金属性能的影响规律,发现该套材料具有非常宽泛的工艺参数适用性.     

不锈钢带极电渣堆焊层金属耐腐蚀性能

采用带极电渣堆焊（ESW）和带极埋弧堆焊（SAW）两种方法在Q235母材上熔敷不锈钢层,分析了这两种方法和不同焊接速度下得到的堆焊层金属的电化学腐蚀及晶间腐蚀性能.电化学腐蚀结果表明,9.8%H2SO4溶液中,当扫描电位低于-300 mV时,堆焊层金属即可进入钝化状态,堆焊层金属（ESW v=8 m/h）的电化学腐蚀性...     

焊条电弧焊对2205双相不锈钢焊接接头综合性能影响的研究

采用焊条电弧焊焊接工艺方法焊接2205双相不锈钢,研究了焊条电弧焊对2205双相不锈钢焊接接头组织及力学性能的影响,同时研究了E2209焊条熔敷金属的抗腐蚀性能.研究结果表明:E2209焊条熔敷金属具有优良的抗腐蚀性能;采用适当的焊接热输入,可获得具有合理相比例并且力学性能优良的接头.     

奥氏体不锈钢带极电渣堆焊层金属显微组织分析

奥氏体不锈钢具有良好的焊接性、优异的抗腐蚀性、良好的高温抗氧化性和低温韧性,应用广泛。采用自行研制的焊剂配合奥氏体不锈钢焊带在低碳钢母材Q235上进行堆焊,焊后采用金相、扫描电镜等试验方法对堆焊层金属的显微组织和性能进行了研究,分析奥氏体不锈钢焊接接头显微组织的变化,并深入研究焊缝中δ-铁素体的含量和分布形态。研究结果表明,带极电渣堆焊层金属成型性好、稀释率低,其显微组织为奥氏体和少量的δ-铁素体,其中δ-铁素体的形态有骨架状、板条状、蠕虫状三种共存于堆焊层金属中,一定数量的δ-铁素体可以保证堆焊层金属有良好的耐晶间腐蚀性能。     

高强度不锈钢焊带堆焊层力学性能研究

对普通堆焊层与高强度堆焊层焊材、熔敷金属化学成分以及堆焊层焊态、热处理态下拉伸性能进行了试验分析,研究影响容器不锈钢堆焊层拉伸性能的主要因素。研究表明:添加N元素可以提高不锈钢堆焊层的抗拉强度;308L型不锈钢堆焊层抗拉强度和断后伸长率受消应力热处理时间的影响较小;随着消应力热处理时间的增加(0～40h),309L型不锈钢堆焊层抗拉强度先提高后下降,且铁素体含量对309L型不锈钢堆焊层断后伸长率的下降趋势有较大影响。     

DSS2205轧制与爆炸复合板复层组织与性能分析

采用实验室化学浸泡、电化学腐蚀试验及维氏硬度测量技术研究了DSS2205爆炸及热轧复合板复层性能,利用金相显微镜、透射电镜分析了复层组织,并与复合前的DSS2205进行了对比分析。结果表明：相比复合前的DSS2205不锈钢,轧制和爆炸复合板复层腐蚀性能略有下降,硬度增加,但轧制复合板复层腐蚀性能优于爆炸复合板复层;轧制复合板复层组织为棒状奥氏体不完全呈一条直线分布于铁素体上,奥氏体发生再结晶;爆炸复合板复层仍为复合前的奥氏体和铁素体间隔分布带状组织,铁素体和奥氏体均出现变形。     

The Microstructure and Pitting Resistance of Weld Joints of 2205 Duplex Stainless Steel

2205 duplex stainless steel (DSS) was welded by submerged arc welding. The effects of both heat input and groove type on the ferrite/austenite ratio and elemental diffusion of weld joints were investigated. The relationships among welding joint preparation, ferrite/austenite ratio, elemental diffusion, and pitting corrosion resistance of weld joints were analyzed. When the Ni content of the weld wire deposit was at minimum 2–4% higher than that of 2205 DSS base metal, the desired ratio of ferrite/austenite and elemental partitioning between the austenite and ferrite phases were obtained. While the pitting sensitivity of weld metal was higher than that of base metal, the self-healing capability of the passive film of weld metal was better than that of the base metal when a single V-type groove was used. Furthermore, the heat input should be carefully controlled since pitting corrosion occurred readily in the coarse-grained heat-affected zone near the fusion line of welded joints.     

焊接方法对双相不锈钢焊接接头耐蚀性的影响

采用气体保护钨极氩弧焊（GTAW）、焊条电弧焊（SMAW）和埋弧焊（SAW）对2205双相不锈钢进行焊接,采用光学显微镜对接头组织进行观察,采用数点法计算铁素体相的含量,测定接头的耐点蚀和耐CO2应力腐蚀性能,研究焊接方法对接头耐蚀性的影响。结果表明,焊接方法影响焊缝组织形态及铁素体含量。GTAW焊缝由不规则的条状组织和两相交织分布的块状组织组成,而SMAW和SAW焊缝为方位不一的条状组织和少量的块状组织。GTAW和SMAW焊缝的铁素体含量为35％～55％,而SAW的不足20％。接头的耐蚀性与铁素体相比例密切相关,GTAW、SMAW和SAW的耐蚀性依次降低。从铁素体相比例和耐蚀性角度考虑,GTAW和SMAW能够获得满意的焊接接头。     

磁场作用下2205双相不锈钢焊缝成形与组织特征

采用摆动电弧GTAW对2205双相不锈钢进行了自熔焊接.研究了不同励磁电流下焊缝截面的特征以及其对焊缝组织的影响.结果表明,摆动电弧可以促进接头的熔合,但随着励磁电流增加,熔合效果逐渐变差.摆动电弧可促进2205双相不锈钢焊缝中奥氏体的析出并可使铁素体得到细化,在励磁电流1 A下,效果最佳.奥氏体含量的增加缓解了由于相比例失衡所致的硬度值升高,使得焊缝硬度更加接近母材.     

超低氢高韧性无缝药芯焊丝TME711NiSF的研制

通过选择钛碱性渣系和Mn-Si-Ni-Ti-B合金系,在德国进口无缝药芯焊丝生产线上,制成了一种超低氢高韧性的无缝药芯焊丝TME711NiSF. 其焊接工艺性能和力学性能优良,对焊接热输入具有良好的适应性. 为探讨熔敷金属的韧化机理,对配方中的脱氧剂和合金剂含量进行了优化设计. 结果表明,Mn和Si元素含量居于优化水平时,焊缝组织主要是均匀细小的针状铁素体,这种组织的塑性和低温韧性高,熔敷金属在温度-40 ℃冲击吸收功可达到154 J. 该无缝药芯焊丝熔敷金属的扩散氢含量为2.4 mL/100 g,达到了超低氢水平,适用于船舶、桥梁、海洋工程等重要结构的焊接.     

Effect of delta ferrite content on the corrosion resistance of type 316 clad metals

Austenitic claddings of type 316 were obtained by SMAW (Shielded Metal Arc Welding) and SAW (Submerged Arc Welding) processes, using type 316 L electrodes on low carbon boiler steel (SA 515 Gr 60) with type 309 L as a barrier layer deposited by the SAW process. Welding heat input was changed in order to obtain different ferrite contents in the cladding. The clad samples were post-weld heat treated at 650°C for 50 and 200 h. The top layer of the cladding was removed and the specimens were then subjected to intergranular corrosion tests (ASTM A-262-75, practices A, B, C and E, viz. 10% oxalic acid electrolytic etch; ferric sulfate ?50% sulfuric acid; 65% nitric acid and copper-copper sulfate ?16% sulfuric acid tests) and controlled potential etching test. The study indicated that the ferrite content of the cladding decreases with increasing current. Ferrite transformed after PWHT (post weld heat treatment) was relatively more in claddings obtained with low heat input and containing high ferrite content in the as-clad condition. PWHT led to brittle fracture of high ferrite claddings (above 10 FN). The corrosion attack of ferrite was found to depend on environment. 65% nitric acid attacked ferrite preferentially, whereas in acid-ferric sulfate, ferrite was intact and austenite was attacked. No sample exhibited susceptibility to intergranular corrosion in the as-clad or PWHT conditions in the copper-copper sulfate ?16% acid test. However, PWHT specimens with low ferrite contents (3.55 FN) exhibited grain boundary precipitation at the interface of two adjacent layers. In general, ferrite was found to be beneficial in controlling corrosion rates of clad metals after PWHT. Heat input, within the range studied, did not affect the corrosion rates significantly.     

2205双相不锈钢焊接接头微区耐点蚀性能分析

采用光学显微镜观察了2205双相不锈钢焊接接头的组织形貌,采用自制的微电化学测试系统测量了母材、焊缝和HAZ的微区循环伏安曲线.结果表明,2205双相不锈钢焊接接头的组织为铁素体＋奥氏体,焊缝中铁素体含量约为48%,与母材相当,HAZ中铁素体平均含量高于50%;在3.5%的NaCl溶液中2205双相不锈钢焊接接头焊缝微...     

焊接速度对18-8不锈钢堆焊层组织形态的影响

采用带极电渣焊方法在Q235表面得到了18-8不锈钢堆焊层。研究不同焊接速度对18-8不锈钢堆焊层组织形态的影响。结果表明,带极电渣堆焊层显微组织主要由奥氏体和少量δ铁素体构成,其中δ铁素体有断续状(或称蠕虫状)、骨架状和板条状三种形态,决定于堆焊层的合金成分、焊接热输入及冷却条件等因素。当焊速过小时,堆焊层组织中δ铁素体的形态主要是断续状和骨架状;当焊速过大时,δ铁素体的形态主要是板条状和骨架状;当焊速适中时,可获得热输入小、稀释率低、成形良好,显微组织为奥氏体基体和骨架状δ铁素体的堆焊层组织。     

Effect on the chemical activity of flux on the properties of deposited metal in electroslag welding and remelting

The effect of the chemical activity of flux on the properties of deposited metal of Mn–Ni–Mo–V steels, produced by electroslag welding and electroslag remelting, is discussed. It is shown that an increase in the chemical activity of flux by increasing its silica content to 16–24% (FTs-21 flux) in the remelted metal increases the fraction of easily deformed non-metallic oxide inclusions and the number of zones with reduced hardness in the structure of the metal. This increases the elasticity properties and strain capacity of the metal in the process of relaxation of welding stresses and in the formation of the required mechanical properties of the welded joints after final heat treatment. Also, the risk of formation of reheat cracks in the electroslag welded joints is reduced.