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20G seamless steel cryogenic deformation and annealing studi

20G seamless steel pipe is a high-quality carbon structural steel, boiler material, the carbon content of 0.17-0.24%, tensile strength of 410Mpa, yield point 230-250Mpa. Is our main production of steel, we can provide 20G Seamless pipe with high quality and competitive price. Here to introduce you to our 20G seamless pipe basic chemical properties and mechanical properties. 20G seamless steel cryogenic deformation and annealing studi
20G seamless steel cryogenic deformation and annealing studies 12Cr1MoVG

20G and 12Cr1MoVG boilers with high-quality carbon steel, alloy steel representatives, in practice, has been widely used and developed. 12Cr1MoVG is the early development of successful application of the more mature and strong low-alloy steel pearlite heat, low carbon content, technology, thermal conductivity, and has a high creep rupture strength and ductility. Generally used in the manufacture of steam at temperatures below 540 ℃ collection box, steam pipes, metal wall temperature does not exceed 580 ℃ superheater, reheater and some casting and forging, high-parameter power plant is currently the most common main steam pipes, tubes of steel reheat. With the needs of the operating parameters and unit capacity of the power plant units as well as a sharp increase in temperature boiler to large diameter pipeline development, and promote the further study of high-temperature high-strength boiler tubes, and produce domestic hot-rolled (pull) the largest seamless steel pipe outside path specifications of 720mm, larger diameter seamless steel pipe thermal expansion path only through other processes to achieve. Relatively high production costs and production equipment is expensive in terms of hot-rolled seamless steel tubes used with the production process is simple, stable quality, economical and practical features of standard thermal expansion push technology, you can make pipe diameter increases in a short period of time, and low-cost, high production efficiency.

Precisely because of this, as smelting, pushing standard hot-rolled steel pipe mainline expansion extends well to fill the domestic major steel production of non-standard and special types of large diameter seamless steel pipe blank lack solve the special needs of users .

Standard push a special thermomechanical treatment process is the essence of thermal expansion pipe. Through low-temperature deformation and annealing 12Cr1MoVG 20G seamless steel pipe and through the original heat-treated steel subsequent comparative analysis study microstructure, mechanical properties at room temperature, etc., and with reference to GB5310-2008 standards were evaluated.

Experiment with the chemical composition of the material to meet the requirements of GB5310-2008. Push standard cryogenic deformation annealing specification main parameters are: 20G (Flaring temperature 80 ~ 730 ℃, expanded diameter ratio 1.30, flaring speed 300mm / min, coil size 750mm, coil frequency 2500Hz and 910 ℃ normalizing heat treatment); 12Cr1MoVG (expansion tube temperature 750 ~ 800 ℃, expanded diameter ratio 1.27, flaring speed 170mm / min, coil size 750mm, coil frequency 2500Hz and 990 ℃ normalizing + 740 ℃ tempering).

The results showed that the use of low-temperature deformation annealing standard push production 20G, 12Cr1MoVG seamless thermal expansion pipe retained ferrite + pearlite structure of the original pipe, its grain size, non-metallic inclusions and room temperature mechanical properties are reached GB5310-2008 the request, from an economic cost, energy saving and low-carbon economy today advocated the practical requirements of view, 12Cr1MoVG subsequent heat treatment may be omitted. 20G seamless band structure produced after the original tube cryogenic deformation annealing, can be eliminated by subsequent normalizing heat treatment, and subsequent heat treatment tube has good overall performance, meet the requirements of GB5310-2008.

20G和12Cr1MoVG无缝钢管低温形变退火研究

Seamless steel pipe Q245R grade (equal to 20G)
57mm cutting end


Out diameter 42mm all

20G和12Cr1MoVG作为锅炉用优质碳素钢、合金钢的代表,在实践中已经得到广泛的应用和发展。12Cr1MoVG是较早开发成功,应用较成熟的低合金珠光体热强钢,含碳量较低,工艺性、导热性好,具有较高的持久强度和持久塑性。一般用于制造蒸汽温度在540℃以下的集箱、蒸汽管道,金属壁温不超过580℃的过热器、再热器及部分铸锻件,是目前高参数火力发电厂中应用最普遍的主蒸汽管道、再热器管道用钢之一。随着我国电站机组运行参数和单机容量的急剧增加以及高温锅炉管道向大口径发展的需要,促进了高温高强锅炉管的进一步研究,而目前国内可生产的热轧(拔)无缝钢管最大外径规格达720mm,更大直径的无缝钢管只能通过热扩径工艺等来实现。较生产成本高和生产设备昂贵的热轧无缝钢管而言,采用具有生产流程简单、质量稳定、经济实用等特点的推制式热扩工艺,可以在较短的时间内使钢管直径增大,且成本低,生产效率高。也正因为如此,作为冶炼、轧管主线延伸的推制式热扩钢管很好的填补了国内外各大钢厂生产非标、特殊型号大口径无缝钢管欠缺的空白,解决了用户的特殊需求。

推制式热扩钢管过程实质为一种特殊的形变热处理。通过对低温形变退火处理的20G和12Cr1MoVG无缝钢管、原管以及经后续热处理后的钢管在显微组织、室温力学性能等方面进行对比分析研究,并参考GB5310-2008标准进行了评价。

实验用材料的化学成分符合GB5310-2008的要求。推制式低温形变退火规范主要参数是:20G(扩管温度80~730℃、扩径比1.30、扩管速度300mm/min,线圈规格750mm、线圈频率2500Hz以及910℃正火热处理);12Cr1MoVG(扩管温度750~800℃、扩径比1.27、扩管速度170mm/min,线圈规格750mm、线圈频率2500Hz以及990℃正火+740℃回火)。

结果显示,采用推制式低温形变退火生产的20G、12Cr1MoVG无缝热扩钢管保留了原管的铁素体+珠光体组织,其晶粒度、非金属夹杂物和室温力学性能均达到GB5310-2008的要求,从经济成本、节能减排以及现今提倡低碳经济的现实要求上看,12Cr1MoVG后续的热处理可以省略。20G无缝原管低温形变退火后产生的带状组织,可以通过后续正火热处理得到消除,且后续热处理管具有较好的综合性能,符合GB5310-2008的要求



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