起重機主梁下沉的原因有哪些

？

qizhongjizhulianggongdudezhujianjianxiaochengzhiweizhuliangxiachen，jiziyuanshigongduxiangxiachanshengleyongjiubianxing。guidingzhuliangshuipingyixiayongjiubianxingchengweixianao。zhuliangxiachendeyuanyinzhu要有以下幾種：

1
、不合理的使用：qizhongjishizaizhidingdeshiyongtiaojianxiajinxingshejide
，duiyuchaozaijiqitabuhelideshiyongshiwufajinxingkaolvde。danshibushaoshiyongdanweiduicibugouzhongshi，changqichaozaihegaibiangongzuoleixingshiyong
，haiyouyongyutuolazhongwu、拔地腳螺栓等。根據調查
，不少單位的起重機就是因為這種不合理的使用損壞的。

2、不合理的修理：由you於yu沒mei有you掌zhang握wo起qi重zhong機ji金jin屬shu結jie構gou上shang加jia熱re引yin起qi結jie構gou變bian形xing的de規gui律lv，因yin而er也ye沒mei有you采cai取qu防fang止zhi變bian形xing的de措cuo施shi
，就jiu在zai橋qiao架jia上shang氣qi割ge或huo焊han接jie

，從cong而er造zao成cheng主zhu梁liang的de嚴yan重zhong變bian形xing，此ci外wai，在zai走zou台tai上shang加jia熱re會hui造zao成cheng主zhu梁liang向xiang內nei旁pang彎wan，在zai端duan梁liang上shang加jia熱re，不bu僅jin端duan梁liang上shang回hui變bian形xing，而er且qie會hui影ying響xiang主zhu梁liang變bian形xing。所suo以yi，應ying掌zhang握wo金jin屬shu結jie構gou的de變bian形xing規gui律lv，盡jin量liang避bi免mian在zai結jie構gou上shang加jia熱re，必bi須xu焊han接jie或huo氣qi割ge時shi，應ying視shi具ju體ti情qing況kuang，采cai取qu防fang止zhi變bian形xing的de措cuo施shi。

3、起重機不合理的起吊、存放、運輸和安裝：起重機橋架為長大結構件，彈性較大
，不合理的存放
、運輸、起(qi)吊(diao)和(he)安(an)裝(zhuang)都(dou)可(ke)能(neng)引(yin)起(qi)橋(qiao)架(jia)結(jie)構(gou)的(de)變(bian)形(xing)。起(qi)重(zhong)機(ji)的(de)使(shi)用(yong)單(dan)位(wei)應(ying)注(zhu)意(yi)合(he)理(li)使(shi)用(yong)
，遵(zun)守(shou)操(cao)作(zuo)規(gui)程(cheng)和(he)必(bi)要(yao)的(de)製(zhi)度(du)
，這(zhe)對(dui)延(yan)長(chang)使(shi)用(yong)壽(shou)命(ming)和(he)防(fang)止(zhi)起(qi)重(zhong)機(ji)主(zhu)梁(liang)下(xia)沉(chen)極(ji)其(qi)重(zhong)要(yao)。

4、高溫影響：genjutiaocha，rejiagongchejianshiyongdeqizhongjibilengjiagongchejianshiyongdeqizhongjidezhuliangxiachenxianxianggengweipubian
，xiachendechengduyeyueyanzhong，zhezhonggaowenhuanjingduoshushifushereyinqide。zheshiyinweigaowenhuanjing
，zaiyidingchengdushangyaojiangdijinshucailiaodequfuqiangdu，lingyifangmianshangshugaowenhuanjing，jiangchanshengwenduyingli，zhejiuzengjialezhuliangxiachendekenengxing。jiaoweituchudeshi，yelianfusherejiangzaochengzhuliangdexiagaibandadachaoguoshanggaibanwendu
，shishidexiagaibandeshoureshenchangdayushanggaibandeshoureshenchang，zaizaihedezuoyongxiadaozhilezhulianggongdudeziranjianxiao。suoyi，zaiyoufusherehuanjingzhongshiyongqizhongji，jinshujiegouxiabuyingzengjiagerecuoshi，yijianshaogaowenduijinshujiegoudeyingxiang。

5
、結構內應力的影響：起重機金屬結構的各部位存在不同方向的拉、壓(ya)等(deng)效(xiao)應(ying)力(li)。這(zhe)些(xie)力(li)飛(fei)產(chan)生(sheng)，主(zhu)要(yao)是(shi)結(jie)構(gou)製(zhi)造(zao)過(guo)程(cheng)中(zhong)的(de)強(qiang)製(zhi)組(zu)裝(zhuang)構(gou)建(jian)變(bian)形(xing)造(zao)成(cheng)的(de)。另(ling)外(wai)，由(you)於(yu)焊(han)接(jie)過(guo)程(cheng)中(zhong)的(de)局(ju)部(bu)不(bu)均(jun)勻(yun)加(jia)熱(re)

，將(jiang)會(hui)造(zao)成(cheng)焊(han)縫(feng)及(ji)附(fu)近(jin)金(jin)屬(shu)的(de)收(shou)縮(suo)，導(dao)致(zhi)主(zhu)梁(liang)內(nei)部(bu)產(chan)生(sheng)殘(can)餘(yu)內(nei)應(ying)力(li)，從(cong)而(er)在(zai)負(fu)荷(he)作(zuo)用(yong)下(xia)，將(jiang)使(shi)得(de)主(zhu)梁(liang)產(chan)生(sheng)很(hen)大(da)的(de)應(ying)力(li)而(er)引(yin)起(qi)永(yong)久(jiu)變(bian)形(xing)。結(jie)構(gou)殘(can)餘(yu)內(nei)應(ying)力(li)
，在(zai)起(qi)重(zhong)機(ji)的(de)使(shi)用(yong)過(guo)程(cheng)中(zhong)將(jiang)不(bu)斷(duan)趨(qu)於(yu)均(jun)勻(yun)化(hua)以(yi)至(zhi)消(xiao)失(shi)，從(cong)而(er)引(yin)起(qi)主(zhu)梁(liang)的(de)下(xia)沉(chen)。