（1）工程(cheng)機(ji)械使(shi)(shi)(shi)用(yong)(yong)(yong)初期(qi)(qi)(qi)(qi)(qi)階(jie)段(duan)的(de)故(gu)(gu)(gu)障(zhang)特點。工程(cheng)機(ji)械在(zai)使(shi)(shi)(shi)用(yong)(yong)(yong)初期(qi)(qi)(qi)(qi)(qi)(相(xiang)當(dang)于(yu)走(zou)(zou)合(he)期(qi)(qi)(qi)(qi)(qi))其(qi)故(gu)(gu)(gu)障(zhang)是由(you)高到低(di)(di)(降(jiang)曲線)，使(shi)(shi)(shi)用(yong)(yong)(yong)初期(qi)(qi)(qi)(qi)(qi)故(gu)(gu)(gu)障(zhang)率(lv)高低(di)(di)是隨(sui)制(zhi)造或(huo)(huo)維(wei)修質量(liang)和走(zou)(zou)合(he)時(shi)期(qi)(qi)(qi)(qi)(qi)的(de)使(shi)(shi)(shi)用(yong)(yong)(yong)有關．如(ru)果(guo)工程(cheng)機(ji)械制(zhi)造或(huo)(huo)修理(li)質量(liang)高，并(bing)能(neng)正確地使(shi)(shi)(shi)用(yong)(yong)(yong)與維(wei)護。那(nei)么，初期(qi)(qi)(qi)(qi)(qi)故(gu)(gu)(gu)障(zhang)率(lv)就低(di)(di)。否則早期(qi)(qi)(qi)(qi)(qi)故(gu)(gu)(gu)障(zhang)率(lv)會(hui)高。早期(qi)(qi)(qi)(qi)(qi)故(gu)(gu)(gu)障(zhang)多地是聯接(jie)(jie)螺栓松(song)動或(huo)(huo)松(song)脫；管道接(jie)(jie)頭松(song)動或(huo)(huo)松(song)脫：殘留金屬屑(xie)或(huo)(huo)鑄造砂易堵塞油(you)道或(huo)(huo)夾(jia)在(zai)相(xiang)對運動摩擦中拉傷機(ji)件(jian)(如(ru)液壓(ya)系(xi)統中的(de)執行機(ji)構(gou)油(you)缸(gang))造成漏(lou)油(you)，調整后(hou)的(de)間隙或(huo)(huo)壓(ya)力(li)發生(sheng)變(bian)化，使(shi)(shi)(shi)機(ji)件(jian)不能(neng)執行規定能(neng)力(li)，有些接(jie)(jie)合(he)因(yin)螺栓不緊而漏(lou)水、漏(lou)油(you)、漏(lou)氣等。

（2）工(gong)程機械正(zheng)常(chang)使(shi)用(yong)階段的故障(zhang)(zhang)特點。工(gong)程機械走合期結(jie)束(shu)后，進人(ren)正(zheng)常(chang)使(shi)用(yong)階段。工(gong)程機械在這個階段內運行(xing)，只要按規定維(wei)護和正(zheng)確使(shi)用(yong)，一般不會(hui)發(fa)生(sheng)故障(zhang)(zhang)，即便發(fa)生(sheng)故障(zhang)(zhang)，也是隨機性的故障(zhang)(zhang)。