45Mn2無縫鋼管力學(xue)性(xing)(xing)能(neng)(neng)是(shi)保證鋼(gang)材最終使(shi)用性(xing)(xing)能(neng)(neng)(機械性(xing)(xing)能(neng)(neng))的(de)重要指(zhi)標(biao)，它(ta)取決于鋼(gang)的(de)化(hua)學(xue)成分和熱處理制度(du)(du)。在鋼(gang)管(guan)標(biao)準(zhun)中，根據不同的(de)使(shi)用要求，規定了拉伸(shen)性(xing)(xing)能(neng)(neng)(抗拉強度(du)(du)、屈服(fu)(fu)強度(du)(du)或(huo)屈服(fu)(fu)點、伸(shen)長率)以及硬度(du)(du)、韌性(xing)(xing)指(zhi)標(biao)，還(huan)有用戶(hu)要求的(de)高、低溫性(xing)(xing)能(neng)(neng)等。

　　①抗(kang)拉(la)(la)強度(σb)試樣在拉(la)(la)伸過程中(zhong)，在拉(la)(la)斷時所(suo)承受的(de)(de)大力(li)(Fb)，除以試樣原橫截面積(So)所(suo)得的(de)(de)應力(li)(σ)，稱為抗(kang)拉(la)(la)強度(σb)，單(dan)位為N/mm2(MPa)。它表示金(jin)屬(shu)材料在拉(la)(la)力(li)作用(yong)下抵抗(kang)破(po)壞的(de)(de)大能力(li)。

　　②屈服(fu)(fu)(fu)(fu)點(dian)(dian)(dian)(σs)具(ju)有(you)屈服(fu)(fu)(fu)(fu)現象的(de)金屬材料(liao)，試(shi)樣(yang)(yang)在拉伸過程(cheng)(cheng)中力(li)不(bu)增加(保持(chi)恒定)仍能繼續伸長時的(de)應力(li)，稱屈服(fu)(fu)(fu)(fu)點(dian)(dian)(dian)。若力(li)發生下降(jiang)時，則應區分上(shang)、下屈服(fu)(fu)(fu)(fu)點(dian)(dian)(dian)。屈服(fu)(fu)(fu)(fu)點(dian)(dian)(dian)的(de)單位(wei)為(wei)N/mm2(MPa)。上(shang)屈服(fu)(fu)(fu)(fu)點(dian)(dian)(dian)(σsu)：試(shi)樣(yang)(yang)發生屈服(fu)(fu)(fu)(fu)而(er)力(li)下降(jiang)前的(de)大應力(li); 下屈服(fu)(fu)(fu)(fu)點(dian)(dian)(dian)(σsl)：當不(bu)計初始(shi)瞬時效應時，屈服(fu)(fu)(fu)(fu)階(jie)段(duan)中的(de)小應力(li)。屈服(fu)(fu)(fu)(fu)點(dian)(dian)(dian)的(de)計算公式(shi)為(wei)：式(shi)中：Fs--試(shi)樣(yang)(yang)拉伸過程(cheng)(cheng)中屈服(fu)(fu)(fu)(fu)力(li)(恒定)，N(牛頓(dun))So--試(shi)樣(yang)(yang)原始(shi)橫截面積，mm2。

　　③斷后伸長率(σ)在拉(la)伸試(shi)驗中(zhong)，試(shi)樣(yang)拉(la)斷后其標距所增加的長度(du)(du)與原標距長度(du)(du)的百分比，稱為(wei)伸長率。以σ表示，單(dan)位為(wei)%。計(ji)算公式為(wei)：σ=(Lh-Lo)/L0*100%式中(zhong)：Lh--試(shi)樣(yang)拉(la)斷后的標距長度(du)(du)，mm; L0--試(shi)樣(yang)原始標距長度(du)(du)，mm。

　　④斷面(mian)(mian)收縮率(lv)(lv)(ψ)在(zai)拉伸試驗中(zhong)，試樣(yang)拉斷后(hou)其縮徑處橫截(jie)面(mian)(mian)積的大縮減量與原(yuan)始橫截(jie)面(mian)(mian)積的百分比(bi)，稱為斷面(mian)(mian)收縮率(lv)(lv)。以ψ表示，單(dan)位(wei)為%。計算(suan)公式如下：式中(zhong)：S0--試樣(yang)原(yuan)始橫截(jie)面(mian)(mian)積，mm2; S1--試樣(yang)拉斷后(hou)縮徑處的最少橫截(jie)面(mian)(mian)積，mm2。

　　⑤硬(ying)(ying)(ying)(ying)(ying)(ying)(ying)度(du)(du)(du)(du)(du)指(zhi)標金屬(shu)材(cai)(cai)料(liao)抵抗硬(ying)(ying)(ying)(ying)(ying)(ying)(ying)的(de)(de)(de)物體壓(ya)(ya)(ya)(ya)陷表(biao)(biao)(biao)面(mian)(mian)的(de)(de)(de)能(neng)力(li)(li)，稱為硬(ying)(ying)(ying)(ying)(ying)(ying)(ying)度(du)(du)(du)(du)(du)。根據試(shi)(shi)(shi)驗(yan)(yan)方法和(he)適(shi)用(yong)范圍不同，硬(ying)(ying)(ying)(ying)(ying)(ying)(ying)度(du)(du)(du)(du)(du)又可分(fen)為布氏(shi)(shi)(shi)硬(ying)(ying)(ying)(ying)(ying)(ying)(ying)度(du)(du)(du)(du)(du)、洛(luo)氏(shi)(shi)(shi)硬(ying)(ying)(ying)(ying)(ying)(ying)(ying)度(du)(du)(du)(du)(du)、維氏(shi)(shi)(shi)硬(ying)(ying)(ying)(ying)(ying)(ying)(ying)度(du)(du)(du)(du)(du)、肖氏(shi)(shi)(shi)硬(ying)(ying)(ying)(ying)(ying)(ying)(ying)度(du)(du)(du)(du)(du)、顯(xian)微硬(ying)(ying)(ying)(ying)(ying)(ying)(ying)度(du)(du)(du)(du)(du)和(he)高(gao)溫硬(ying)(ying)(ying)(ying)(ying)(ying)(ying)度(du)(du)(du)(du)(du)等。對于(yu)管材(cai)(cai)一般(ban)(ban)常用(yong)的(de)(de)(de)有布氏(shi)(shi)(shi)、洛(luo)氏(shi)(shi)(shi)、維氏(shi)(shi)(shi)硬(ying)(ying)(ying)(ying)(ying)(ying)(ying)度(du)(du)(du)(du)(du)三種。A、布氏(shi)(shi)(shi)硬(ying)(ying)(ying)(ying)(ying)(ying)(ying)度(du)(du)(du)(du)(du)(HB)用(yong)一定(ding)(ding)直(zhi)(zhi)徑的(de)(de)(de)鋼(gang)球或(huo)硬(ying)(ying)(ying)(ying)(ying)(ying)(ying)質合金球，以(yi)規(gui)定(ding)(ding)的(de)(de)(de)試(shi)(shi)(shi)驗(yan)(yan)力(li)(li)(F)壓(ya)(ya)(ya)(ya)入式樣表(biao)(biao)(biao)面(mian)(mian)，經規(gui)定(ding)(ding)保持時間后卸(xie)除(chu)試(shi)(shi)(shi)驗(yan)(yan)力(li)(li)，測量試(shi)(shi)(shi)樣表(biao)(biao)(biao)面(mian)(mian)的(de)(de)(de)壓(ya)(ya)(ya)(ya)痕(hen)直(zhi)(zhi)徑(L)。布氏(shi)(shi)(shi)硬(ying)(ying)(ying)(ying)(ying)(ying)(ying)度(du)(du)(du)(du)(du)值是以(yi)試(shi)(shi)(shi)驗(yan)(yan)力(li)(li)除(chu)以(yi)壓(ya)(ya)(ya)(ya)痕(hen)球形表(biao)(biao)(biao)面(mian)(mian)積所(suo)得(de)的(de)(de)(de)商。以(yi)HBS(鋼(gang)球)表(biao)(biao)(biao)示，單位為N/mm2(MPa)。其(qi)計算公式為：式中：F--壓(ya)(ya)(ya)(ya)入金屬(shu)試(shi)(shi)(shi)樣表(biao)(biao)(biao)面(mian)(mian)的(de)(de)(de)試(shi)(shi)(shi)驗(yan)(yan)力(li)(li)，N; D--試(shi)(shi)(shi)驗(yan)(yan)用(yong)鋼(gang)球直(zhi)(zhi)徑，mm; d--壓(ya)(ya)(ya)(ya)痕(hen)平均直(zhi)(zhi)徑，mm。測定(ding)(ding)布氏(shi)(shi)(shi)硬(ying)(ying)(ying)(ying)(ying)(ying)(ying)度(du)(du)(du)(du)(du)較(jiao)準確可靠(kao)，但(dan)一般(ban)(ban)HBS只(zhi)適(shi)用(yong)于(yu)450N/mm2(MPa)以(yi)下的(de)(de)(de)金屬(shu)材(cai)(cai)料(liao)，對于(yu)較(jiao)硬(ying)(ying)(ying)(ying)(ying)(ying)(ying)的(de)(de)(de)鋼(gang)或(huo)較(jiao)薄的(de)(de)(de)板(ban)材(cai)(cai)不適(shi)用(yong)。在鋼(gang)管標準中，布氏(shi)(shi)(shi)硬(ying)(ying)(ying)(ying)(ying)(ying)(ying)度(du)(du)(du)(du)(du)用(yong)途(tu)最廣，往往以(yi)壓(ya)(ya)(ya)(ya)痕(hen)直(zhi)(zhi)徑d來表(biao)(biao)(biao)示該材(cai)(cai)料(liao)的(de)(de)(de)硬(ying)(ying)(ying)(ying)(ying)(ying)(ying)度(du)(du)(du)(du)(du)，既直(zhi)(zhi)觀(guan)，又方便。舉例：120HBS10/1000/30：表(biao)(biao)(biao)示用(yong)直(zhi)(zhi)徑10mm鋼(gang)球在1000Kgf(9.807KN)試(shi)(shi)(shi)驗(yan)(yan)力(li)(li)作用(yong)下，保持30s(秒(miao))測得(de)的(de)(de)(de)布氏(shi)(shi)(shi)硬(ying)(ying)(ying)(ying)(ying)(ying)(ying)度(du)(du)(du)(du)(du)值為120N/ mm2(MPa)。