近年来随着石油资源的枯竭，新开发的油井、气井许多处于高温、高压环境中，而且这些工业生产用流体一般含有CO2，使输送管道的腐蚀变得越来越严重，作为管道管用耐腐蚀材料，以往一直使用双相不锈钢等。虽然双相不锈钢具有良好的耐蚀性，但材料成本非常高，而且焊接时的焊接线能量控制困难。另一方面，马氏体不锈钢由于焊接性低、焊接时需要预热、而且焊后热处理时间长，影响管道的敷设效率，因此基本不使用这种材料，但由于马氏体不锈钢具有良好的耐CO2腐蚀性，而且成本比双相不锈钢低，因此日本JFE钢公司通过采用先进的炼钢技术，降低C和N，开发了焊接性、耐蚀性和机械特性好的管道管用马氏体不锈钢无缝钢管，即KL-HP12CR。降低C后可提高耐CO2腐蚀性，在温度160℃、压力2.0MPa的CO2腐蚀环境下，腐蚀速度降到0.127mm/年以下。另外，通过添加Mo，提高了耐硫化物应力腐蚀裂纹性，它可用于pH4.0、压力0.001MPa的H2S环境下。该钢管的强度为80X级，用作管道管材料在实际使用上具有充分的低温韧性。通过数分钟的焊后热处理、减少C含量，添加Ti，能有效防止焊接热影响区发生晶间应力腐蚀裂纹。该钢管作为一种寿命周期成本低的材料今后将扩大应用于输送含有CO2等腐蚀性气体的工业生产用流体。
Martensitic stainless steel seamless pipe line with the new KL-HP12CR has excellent weldability, mechanical properties and corrosion resistance. By reducing the carbon and nitrogen to improve its weldability.
Martensitic stainless steel seamless pipe line with the new KL-HP12CR has excellent weldability, mechanical properties and corrosion resistance. By reducing the carbon and nitrogen to improve its weldability. Reduce the carbon content was also significantly improved the corrosion resistance of carbon dioxide, at temperatures up to 160 ℃ and 2.0MPa of the corrosion rate of carbon dioxide in the environment than 0.127mm / a. The addition of molybdenum improves resistance to sulfide stress corrosion cracking (SSC). The new pipe can be used for pH 4.0 and 0.001MPa of hydrogen sulfide environment. This strength of X80 grade steel, used in the pipeline when the actual temperature with sufficient toughness. PWHT a few minutes, reduce the carbon content and add titanium can effectively prevent the heat affected zone intergranular stress corrosion cracking (IGSCC). This steel is expected to be further used to transport liquids containing corrosive gases such as carbon dioxide is a high life-cycle cost economic material.
Reduce people's concern for oil increasing, the current oil and gas wells are being mined the temperature and pressure has reached an unprecedented height, the liquid extracted generally contain carbon dioxide, thus causing more corrosion. Therefore, to remove corrosive substances and water prior to delivery when the liquid flow lines and gathering lines to prevent pipeline corrosion by carbon dioxide becomes extremely important. In addition, these fluids often contain trace amounts of hydrogen sulfide, it is also necessary to prevent chloride stress corrosion cracking. In such a corrosive environment, with respect to carbon steel pipe material, the traditional method of corrosion protection is to inject liquid rust inhibitor, rust inhibitor used to prevent corrosion. However, this increase in production costs, especially the offshore pipeline, the less use of anti-rust agent, especially considering the life-cycle costs. Do not use anti-rust agent, another reason is concern for spill pollution. Thus, a need to use anti-rust agent and economical material. Existing pipeline with corrosion resistant alloys, including duplex stainless steel, but the drawback is high cost of materials. By contrast, the martensitic stainless steel welding is usually poor, and the need to preheat and post weld heat treatment longer. Therefore, taking into account the pipeline efficiency, martensitic stainless steel is rarely used in the pipeline. However, the martensitic stainless steel with a suitable corrosion-resistant carbon dioxide, and cheaper than the duplex stainless steel.
To this end, a Japanese steel company to take a lot of steel-making technology measures such as reducing carbon and nitrogen content, control and add alloying elements to improve the welding of martensitic stainless steel, developed with good weldability and corrosion resistance martensitic stainless steel seamless pipe used.