New Hydrogen Measurement Technique and Hydrogen Cracking for Duplex Stainless Steel Weldment

本研究的目的是建立一种能区分奥氏体和铁素体中氢的新的氢分析方法，并通过焊接裂纹试验，对各种双相不锈钢及其焊接接头的临界氢含量进行评定.采用Ferralium 255、Alloy 2205和SUS329J1钢作为母材，采用Ferralium 259、Alloy 2209、SUS329J3L和SUS329J4L作为SMAW焊条。以不同的加热速率将母材和焊缝金属的样品连续加热至1973 K，并对样品中的氢进行真实的测量。在这种新的氢分析技术中，在较低的加热温度下析出的氢来自铁素体，而在较高的加热温度下析出的氢来自奥氏体。可以区分铁素体中的氢和奥氏体中的氢.另一种新的氢分析技术是使用内摩擦测量。双相不锈钢在260K时出现了1.5Hz的内耗峰，峰高与奥氏体中氢含量有关。可以区分铁素体中的氢和奥氏体中的氢.采用数值微分法计算了氢在铁素体和奥氏体中的扩散行为，扩散模型与实验结果吻合较好.通过各种焊接裂纹试验评价了氢含量与氢裂纹特性之间的关系，并确定了不开裂的临界氢含量。

The aims of this investigation is to establish new hydrogen analysis method which can distinguish hydrogen between in the austenite and in the ferrite, and to evaluate the critical hydrogen content not to crack using weld cracking test for various duplex stainless steel and the weldments.1. Ferralium 255, Alloy 2205 and SUS329J1 steel were employed as base metals, and Ferralium 259, Alloy 2209, SUS329J3L and SUS329J4L were used as the SMAW welding rods. The samples from the base metals and weld metals were heated continuously up to 1973K at various heating rates and hydrogen from the samples was measured at real time. In this new hydrogen analysis technique, hydrogen evolved at lower heating temperature was from the ferrite and hydrogen evolved at higher heating temperature was from the austenite. The distinguish between hydrogen in the ferrite and hydrogen in the austenite could be made.2. Another new hydrogen analysis technique was developed using an internal friction measurement performed. The internal friction peak at 1.5Hz was observed at 260K,the peak height was related to the hydrogen content in the austenite for duplex stainless steels. The distinguish between hydrogen in the ferrite and hydrogen in the austenite could be made.3. Hydrogen diffusion behavior in the ferrite and in the austenite was calculated using numerical differential method and the diffusion model was coincident with the experimental results.4. The relation between hydrogen content and hydrogen cracking characteristics was evaluated using various weld cracking tests, and critical hydrogen content not to crack was determined.