X射線(xian)探(tan)傷機(ji)是(shi)有表面(mian)或近表面(mian)缺陷的工(gong)件(jian)被磁(ci)化(hua)後(hou),當缺陷方(fang)向(xiang)與(yu)磁(ci)場方向成(cheng)壹定角(jiao)度(du)時,由(you)於缺(que)陷處(chu)的磁(ci)導(dao)率的變(bian)化(hua),磁(ci)力(li)線(xian)逸出工件表面(mian),產生漏(lou)磁(ci)場,吸附磁(ci)粉形(xing)成(cheng)磁(ci)痕(hen)。從而顯示出不連(lian)續性(xing)的位(wei)置、形(xing)狀和大小。
X射(she)線(xian)是(shi)壹種波(bo)長(chang)很(hen)短的電(dian)磁(ci)波(bo),有很(hen)強(qiang)的穿透能(neng)力,多(duo)年來(lai),人們(men)不斷(duan)的探(tan)索(suo)創(chuang)新,X射(she)線(xian)已經(jing)廣(guang)泛(fan)的應(ying)用與(yu)人們(men)生(sheng)活(huo)、工(gong)作(zuo)領域。但是(shi)不容(rong)忽(hu)視(shi)的壹點(dian)是(shi),X射線(xian)探(tan)傷機(ji)X射線(xian)對(dui)人體健康確有壹定危(wei)害(hai),X射線(xian)照射(she)量越(yue)大,對(dui)人體的損(sun)害(hai)就越(yue)大。X射線(xian)照射(she)量可(ke)在(zai)身體內累(lei)積,其(qi)主(zhu)要(yao)危(wei)害(hai)是(shi)對(dui)人體血(xue)液(ye)成(cheng)分(fen)中的白(bai)細(xi)胞(bao)具(ju)有壹定的殺傷力(li),使(shi)人體血(xue)液(ye)中的白(bai)細(xi)胞(bao)數(shu)量減(jian)少,進(jin)而導(dao)致(zhi)機(ji)體免(mian)疫功能(neng)下降,使(shi)病(bing)菌(jun)容(rong)易(yi)侵(qin)入(ru)機(ji)體而(er)發生疾病。
X射(she)線(xian)探(tan)傷機(ji)的穿透能(neng)力取(qu)決於X射(she)線(xian)探(tan)傷機(ji)的容(rong)量,既X射線(xian)探(tan)傷機(ji)的管(guan)電(dian)壓,管(guan)電(dian)壓愈(yu)高(gao),X射線(xian)愈硬,能(neng)量愈大,穿透能(neng)力就愈(yu)強(qiang),穿透能(neng)力與(yu)管電(dian)壓平方成(cheng)正比(bi)。另(ling)外(wai),在(zai)相同(tong)的管(guan)電(dian)壓下,還與被檢驗(yan)工件(jian)的材(cai)質的密(mi)度(du)等(deng)性(xing)質有關(guan),也(ye)就是(shi)與被檢驗(yan)工件(jian)對(dui)X射(she)線(xian)的衰減(jian)能(neng)力有關(guan)。對(dui)於鋼鐵等(deng)重金屬以及(ji)較厚(hou)的工(gong)件(jian),由(you)於其(qi)對(dui)X射(she)線(xian)的衰減(jian)能(neng)力較(jiao)強(qiang),故(gu)應選(xuan)擇(ze)管(guan)電壓較(jiao)高(gao)的X射(she)線(xian)探(tan)傷機(ji);而對(dui)於鋁(lv)、鎂等(deng)輕(qing)金(jin)屬和較(jiao)薄(bo)的工(gong)件(jian),可(ke)以選(xuan)擇(ze)管(guan)電壓較(jiao)低(di)的X射(she)線(xian)探(tan)傷機(ji)。
對(dui)於圓(yuan)形的工(gong)件(jian),如鍋爐簡體或(huo)容(rong)器上的環焊(han)縫(feng),應首(shou)先考(kao)慮(lv)選(xuan)擇(ze)周向(xiang)曝(pu)光(guang)的射(she)線(xian)探(tan)傷機(ji),以提(ti)高工件效(xiao)率,減(jian)輕(qing)勞(lao)動(dong)強(qiang)度(du),減(jian)少放(fang)射線(xian)損(sun)傷(shang)。
對(dui)於工(gong)件較(jiao)小(xiao),移(yi)動(dong)方便的,可(ke)選(xuan)用移(yi)動(dong)式探(tan)傷機(ji)X射線(xian)探(tan)傷機(ji),而對(dui)工(gong)件笨(ben)重或高大設備(bei),移(yi)動(dong)不方(fang)便,可(ke)選(xuan)用攜帶(dai)式X射(she)線(xian)探(tan)傷機(ji)。