It is infrequence in China that the weld high - temperature high - pressure hydrogenation pipe is cracked short time.高温高压 临氢管道焊缝迅速发生裂纹,国内罕见....

infrequence的音标：infrequence的英式发音音标为：[ɪn'fri:kwəns]infrequence的美式发音音标为：[ɪn'frikwəns]...

n.很少发生，罕见...