To ensure the long-term safe operation of heat-resistant steel welded joints under high temperature, high pressure, and various corrosive media conditions, the performance of pressure vessel automatic welding joints should meet the following requirements.

①接頭的等強(qiáng)性 耐熱鋼接頭不僅應(yīng)具有與母材基本相等的室溫和高溫短時(shí)強(qiáng)度，而且更重要的是應(yīng)具有與母材相近的高溫持久強(qiáng)度。

① The high-strength heat-resistant steel joint of the joint should not only have room temperature and high-temperature short-term strength that is basically equal to the base material, but more importantly, it should have high-temperature endurance strength similar to the base material.

②接頭的抗氫性和抗氧化性 耐熱鋼接頭應(yīng)具有與母材基本相同的抗氫性和高溫抗氧化性。為此，焊縫金屬的合金成分和含量應(yīng)與母材基本一致。

② The hydrogen resistance and oxidation resistance of the joint. The heat-resistant steel joint should have basically the same hydrogen resistance and high-temperature oxidation resistance as the base material. Therefore, the alloy composition and content of the weld metal should be basically consistent with the base metal.

③接頭的組織穩(wěn)定性 耐熱鋼焊接接頭在制造過(guò)程中，特別是厚壁接頭將經(jīng)受長(zhǎng)時(shí)間多次熱處理，在運(yùn)行過(guò)程中將長(zhǎng)期受高溫高壓的作用，接頭各區(qū)不應(yīng)產(chǎn)生明顯的組織變化及由此引起的脆變或軟化。

③ The structural stability of heat-resistant steel welded joints, especially thick walled joints, will undergo multiple heat treatments for a long time during the manufacturing process. During operation, they will be subjected to high temperature and pressure for a long time. There should be no obvious structural changes or resulting embrittlement or softening in each area of the joint.

④接頭的抗脆斷性 雖然耐熱鋼壓力容器大多數(shù)是在高溫下工作，但當(dāng)壓力容器和管道制造完工后將在常溫下進(jìn)行設(shè)計(jì)壓力1.25倍壓力的水壓試驗(yàn)。在安裝檢修完后，要經(jīng)歷水壓試驗(yàn)及冷啟動(dòng)過(guò)程。因此，耐熱鋼焊接接頭亦應(yīng)具有一定的抗脆斷性。

④ Although most heat-resistant steel pressure vessels work at high temperatures, the resistance to brittle fracture of joints will undergo a water pressure test at 1.25 times the design pressure at room temperature after the completion of pressure vessel and pipeline manufacturing. After installation and maintenance, it is necessary to undergo a hydraulic test and a cold start process. Therefore, heat-resistant steel welded joints should also have a certain degree of resistance to brittle fracture.

⑤接頭的物理均一性 耐熱鋼焊接接頭應(yīng)具有與母材基本相同的物理性能。焊縫金屬的熱膨脹系數(shù)和熱導(dǎo)率應(yīng)基本一致，這樣就可避免接頭在高溫運(yùn)行過(guò)程中的熱應(yīng)力。

⑤ The physical homogeneity of the joint is that the welded joint of heat-resistant steel should have basically the same physical properties as the base material. The thermal expansion coefficient and thermal conductivity of the weld metal should be basically consistent, so as to avoid thermal stress in the joint during high-temperature operation.