化工材料貯運罐先前是用普通鋼制成罐體后再在其內面涂層防腐。1980年IMO(國際海事協會)制定的船運化工材料貯運罐的裝載條件,增加了對大罐清洗難易程度的要求。從各種船運裝載條件可能性方面考慮,在國際航運船中,多數采用不(bu)銹(xiu)鋼制造的大罐。隨后在國內航運船方面的大罐亦采用不銹鋼制造。當初開始使用的鋼種為SUS304和SUS304不銹鋼復(fu)合板(ban),其后許多航運裝載化學藥品(化工材料)貯運的大罐多采用SUS316、SUS316L、SUS316不銹鋼復合板。
所謂不(bu)銹鋼(gang)(gang)復合(he)板(ban)(ban)(ban)(ban)(ban)(ban),即不(bu)銹鋼(gang)(gang)板(ban)(ban)(ban)(ban)(ban)(ban)生(sheng)產(chan)廠(chang)將不(bu)銹鋼(gang)(gang)板(ban)(ban)(ban)(ban)(ban)(ban)和普通鋼(gang)(gang)板(ban)(ban)(ban)(ban)(ban)(ban)的(de)(de)(de)(de)半成品(pin)的(de)(de)(de)(de)板(ban)(ban)(ban)(ban)(ban)(ban)面貼(tie)(tie)合(he)在一起(qi),在保持(chi)真空狀(zhuang)態下,將貼(tie)(tie)合(he)面的(de)(de)(de)(de)周圍進行(xing)焊(han)接,再(zai)將焊(han)好夾(jia)層板(ban)(ban)(ban)(ban)(ban)(ban)的(de)(de)(de)(de)半成品(pin)進行(xing)加(jia)(jia)熱,在軋板(ban)(ban)(ban)(ban)(ban)(ban)機上(shang)按厚板(ban)(ban)(ban)(ban)(ban)(ban)軋制(zhi)工藝軋成不(bu)銹鋼(gang)(gang)和普通鋼(gang)(gang)相結合(he)的(de)(de)(de)(de)所謂復合(he)板(ban)(ban)(ban)(ban)(ban)(ban)。從船體和大罐的(de)(de)(de)(de)焊(han)接作業等方面考(kao)慮,船體側壁和傳遞板(ban)(ban)(ban)(ban)(ban)(ban)使用(yong)復合(he)板(ban)(ban)(ban)(ban)(ban)(ban),前后隔板(ban)(ban)(ban)(ban)(ban)(ban)和中心隔板(ban)(ban)(ban)(ban)(ban)(ban)多(duo)數還是使用(yong)不(bu)銹鋼(gang)(gang)板(ban)(ban)(ban)(ban)(ban)(ban)。大貯罐中的(de)(de)(de)(de)隔板(ban)(ban)(ban)(ban)(ban)(ban),為了增加(jia)(jia)罐體的(de)(de)(de)(de)強度(du)可(ke)以加(jia)(jia)工成波浪形狀(zhuang)使用(yong)。
化工材料貯(zhu)運(yun)船(chuan),分類為小(xiao)型(xing)(xing)國內運(yun)輸船(chuan)和中型(xing)(xing)、大(da)型(xing)(xing)的(de)國際運(yun)輸船(chuan),在日本所建(jian)造(zao)(zao)的(de)大(da)多數(shu)是(shi)中型(xing)(xing)國際化工材料貯(zhu)運(yun)大(da)罐運(yun)輸船(chuan),歐洲(zhou)建(jian)造(zao)(zao)則(ze)多數(shu)都是(shi)大(da)型(xing)(xing)的(de)。例(li)如(ru),這種大(da)型(xing)(xing)船(chuan)是(shi)從非洲(zhou)裝(zhuang)載磷酸運(yun)往(wang)印度或中國等,卸載以后,清(qing)洗干凈(jing),再(zai)在附(fu)近港口裝(zhuang)載其(qi)他(ta)藥品(pin),往(wang)返于不(bu)同國家(jia)的(de)港口之(zhi)間。
中型國(guo)際(ji)航運化工材料貯運大(da)(da)罐(guan)船,大(da)(da)約為2萬噸(dun)級,船長(chang)度(du)為約150米,寬度(du)約25米,左舷放(fang)置十個(ge)大(da)(da)罐(guan),右舷放(fang)置十個(ge)大(da)(da)罐(guan),共計20個(ge)大(da)(da)罐(guan)。大(da)(da)罐(guan)容量(liang)(liang)要(yao)符(fu)合船的裝(zhuang)載量(liang)(liang)要(yao)求。為了使化工材料貯運大罐的容量增大就要減輕船體重量,重要途徑是使用高強度的材料,減少板材厚度。為此大多數使用了SUS316L不銹鋼和SUS317L不銹鋼牌號中添加氮,具有高強度和高耐腐蝕性的材料。目前,這種SUS316LN不(bu)銹鋼和SUS317LN已經標準化了。在歐洲這種大型化工材料貯運大罐運輸船,多使用強度和耐腐蝕性俱佳的奧氏體/鐵素體雙相不銹鋼材料。