一些δ铁素体（估计在奥氏体不锈钢焊缝金属中约为4%至8%）的存在，可在厚度大于1/2 in.的重型型材焊接期间或焊接后立即降低或延缓奥氏体焊缝金属对裂纹或开裂的敏感性。然而，相对大量（估计大于约10%）的δ铁素体可能会产生有害影响由于铁素体可能转化为sigma，因此暴露于高温后对焊接件延展性的影响。由于铁素体的这些影响，人们试图对奥氏体焊缝和不锈钢板的最大允许铁素体含量施加限制性限制。本研究是作为一项调查和“一轮调查”的一部分进行的- robin“不锈钢焊接咨询小组委员会对样品的检查，以评估奥氏体不锈钢中δ铁素体的测量所涉及的问题，并确定（1）将要使用的铁素体测量的“标尺”；（2）标尺的校准方法，以及（3）校准所需的试样类型和尺寸。

The presence of some delta ferrite (estimated to be about 4 to 8% in austenitic stainless-steel weld metal can minimize or retard the susceptibility of austenitic weld metal to fissuring or cracking during or immediately after welding of heavy sections greater than about 1/2 in. thick. However, relatively large amounts (estimated to be greater than about 10%) of delta ferrite can have deleterious effects on the ductility of the weldment after exposure to elevated temperatures because of the possible conversion of the ferrite to sigma. Because of these effects of ferrite, attempts have been made to impose restrictive limits on the maximum allowable ferrite content of austenitic welds and stainless-steel plates. The present study was undertaken as part of an investigation and a "round-robin" examination on samples by the Advisory Subcommittee on the Welding of Stainless Steels to evaluate the problems involved in the measurement of delta ferrite in austenitic stainless steels, and to determine (1) the "yardstick" of ferrite measurement to be used, (2) the method of calibration of the yardstick, and (3) the type and size of specimen required for calibration.