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西安2507/2205不鏽鋼管的組織與性能

日期:2024-05-13 00:02
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摘要:<p style="margin:0pt;"> <span style="font-family:宋體;font-size:10.5pt;mso-spacerun:&quot;yes&quot;;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family:&quot;Times New Roman&quot;;mso-font-kerning:1.0000pt;"><span style="font-family:宋體;">西安</span></span><span style="font-family:Calibri;font-size:10.5pt;mso-spacerun:&quot;yes&quot;;mso-bidi-font-family:&quot;Times New Roman&quot;;mso-font-kerning:1.0000pt;mso-fareast-font-family:宋體;">2507</span><span style="font-family:宋體;font-size:10.5pt;mso-spacerun:&quot;yes&quot;;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family:&quot;Times New Roman&quot;;mso-font-kerning:1.0000pt;">/2205<span style="font-family:宋體;">不鏽鋼</span></span><span style="font-family:Calibri;font-size:10.5pt;mso-spacerun:&quot;yes&quot;;mso-bidi-font-family:&quot;Times New Roman&quot;;mso-font-kerning:1.0000pt;mso-fareast-font-family:宋體;"><span style="font-family:宋體;">管的組織與性能</span></span> </p> <p style="margin:0pt;"> <span style="font-family:Calibri;font-size:10.5pt;mso-spacerun:&quot;yes&quot;;mso-bidi-font-family:&quot;Times New Roman&quot;;mso-font-kerning:1.0000pt;mso-fareast-font-family:宋體;"><span style="font-family:宋體;">采用熱穿孔工藝,結合多道次冷軋變形,開發出大口徑</span>2507<span style="font-family:宋體;">無縫鋼管,規格為</span></span><span style="font-family:宋體;font-size:10.5pt;mso-spacerun:&quot;yes&quot;;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family:&quot;Times New Roman&quot;;mso-font-kerning:1.0000pt;">219*20</span><span style="font-family:Calibri;font-size:10.5pt;mso-spacerun:&quot;yes&quot;;mso-bidi-font-family:&quot;Times New Roman&quot;;mso-font-kerning:1.0000pt;mso-fareast-font-family:宋體;">mm<span style="font-family:宋體;">。結果表明:</span><span style="font-family:Calibri;">2507</span><span style="font-family:宋體;">無縫鋼管金相組織優良,鐵素體含量約</span><span style="font-family:Calibri;">45%</span><span style="font-family:宋體;">~</span><span style="font-family:Calibri;">55%</span><span style="font-family:宋體;">。鋼管具有良好的力學性能,低溫衝擊功可達</span><span style="font-family:Calibri;">70J</span><span style="font-family:宋體;">以上。同時,鋼管具有較好的耐點腐蝕性能,腐蝕速率小於</span><span style="font-family:Calibri;">3.0mdd</span><span style="font-family:宋體;">。本次開發的大口徑</span><span style="font-family:Calibri;">2507</span><span style="font-family:宋體;">無縫鋼管化學組成、金相組織及室溫力學性能、低溫衝擊性能均滿足</span><span style="font-family:Calibri;">ASME SA790</span><span style="font-family:宋體;">、</span><span style="font-family:Calibri;">ISO 13680</span><span style="font-family:宋體;">等產品標準要求,可以用於石化、海洋、油氣開采等領域。 </span></span> </p> <p style="margin:0pt;"> <span style="font-family:Calibri;font-size:10.5pt;mso-spacerun:&quot;yes&quot;;mso-bidi-font-family:&quot;Times New Roman&quot;;mso-font-kerning:1.0000pt;mso-fareast-font-family:宋體;"><span style="font-family:宋體;">超級雙相不鏽鋼</span>(UNS 2507)<span style="font-family:宋體;">由於超低碳和高鉻、高鉬、高氮的成分設計,與</span><span style="font-family:Calibri;">UNS S32205</span><span style="font-family:宋體;">雙相不鏽鋼相比,具有更高的強度、更好的耐點腐蝕、耐應力腐蝕性能。目前主要用於各種苛刻環境,尤其是在高氯化物環境中,常用作海水熱交換器、海底油田管道纜、海水淡化等裝置。 </span></span><span style="font-family:Calibri;font-size:10.5pt;mso-spacerun:&quot;yes&quot;;mso-bidi-font-family:&quot;Times New Roman&quot;;mso-font-kerning:1.0000pt;mso-fareast-font-family:宋體;"><br /> </span><span style="font-family:Calibri;font-size:10.5pt;mso-spacerun:&quot;yes&quot;;mso-bidi-font-family:&quot;Times New Roman&quot;;mso-font-kerning:1.0000pt;mso-fareast-font-family:宋體;"><span style="font-family:宋體;">苛刻的酸性油氣田環境中,根據介質濃度、溫度、壓力等工況,可選用的材料主要有馬氏體不鏽鋼、雙相不鏽鋼和鎳基合金等。因此,在一些高溫、高壓、高含</span>CO2<span style="font-family:宋體;">、</span><span style="font-family:Calibri;">H2S</span><span style="font-family:宋體;">環境中常采用鎳基合金材料。而在一些含</span><span style="font-family:Calibri;">CO2</span><span style="font-family:宋體;">、</span><span style="font-family:Calibri;">Cl-</span><span style="font-family:宋體;">且</span><span style="font-family:Calibri;">H2S</span><span style="font-family:宋體;">含量較低的油氣開采環境中,</span><span style="font-family:Calibri;">2507</span><span style="font-family:宋體;">合金由於具有冷加工硬化顯著、抗應力腐蝕性能好、耐點蝕,相對於鎳基合金油井管而言,具有價格低、性能相當等特點,綜合性能則優於馬氏體不鏽鋼。因此得到越來越廣泛的應用,應用形式主要是管材</span><span style="font-family:Calibri;">[1]-[5]</span><span style="font-family:宋體;">。 </span></span><span style="font-family:Calibri;font-size:10.5pt;mso-spacerun:&quot;yes&quot;;mso-bidi-font-family:&quot;Times New Roman&quot;;mso-font-kerning:1.0000pt;mso-fareast-font-family:宋體;"><br /> </span><span style="font-family:Calibri;font-size:10.5pt;mso-spacerun:&quot;yes&quot;;mso-bidi-font-family:&quot;Times New Roman&quot;;mso-font-kerning:1.0000pt;mso-fareast-font-family:宋體;"><span style="font-family:宋體;">通常來講,無縫鋼管尺寸較小時,通過熱擠壓工藝或者熱穿孔工藝,結合冷軋工藝可以生產出符合要求的超級雙相無縫鋼管。但是,對於大口徑超級雙相無縫鋼管,采用熱擠壓工藝生產比較困難,特彆是管材長度要求較長時。因此,針對大口徑</span>(<span style="font-family:宋體;">外徑大於</span><span style="font-family:Calibri;">219mm)</span><span style="font-family:宋體;">、長度較長</span><span style="font-family:Calibri;">(9m</span><span style="font-family:宋體;">以上</span><span style="font-family:Calibri;">)</span><span style="font-family:宋體;">等特殊需求,本公司開展了</span><span style="font-family:Calibri;">2507</span><span style="font-family:宋體;">超級雙相無縫鋼管的研製開發,並形成了批量生產的能力。 </span></span> </p> <p style="margin:0pt;"> <span style="font-family:Calibri;font-size:10.5pt;mso-spacerun:&quot;yes&quot;;mso-bidi-font-family:&quot;Times New Roman&quot;;mso-font-kerning:1.0000pt;mso-fareast-font-family:宋體;">1<span style="font-family:宋體;">、大口徑</span><span style="font-family:Calibri;">2507</span><span style="font-family:宋體;">無縫鋼管的製造流程 </span></span> </p> <p style="margin:0pt;"> <span style="font-family:Calibri;font-size:10.5pt;mso-spacerun:&quot;yes&quot;;mso-bidi-font-family:&quot;Times New Roman&quot;;mso-font-kerning:1.0000pt;mso-fareast-font-family:宋體;"><span style="font-family:宋體;">大口徑</span>2507<span style="font-family:宋體;">合金無縫鋼管的整個開發製造流程可以簡化為:鋼錠冶煉</span><span style="font-family:Calibri;">→</span><span style="font-family:宋體;">鍛造開坯</span><span style="font-family:Calibri;">→</span><span style="font-family:宋體;">管坯加工</span><span style="font-family:Calibri;">→</span><span style="font-family:宋體;">熱穿孔</span><span style="font-family:Calibri;">→</span><span style="font-family:宋體;">冷軋成形</span><span style="font-family:Calibri;">→</span><span style="font-family:宋體;">固溶熱處理</span><span style="font-family:Calibri;">→</span><span style="font-family:宋體;">酸洗</span><span style="font-family:Calibri;">→</span><span style="font-family:宋體;">檢驗</span><span style="font-family:Calibri;">→</span><span style="font-family:宋體;">成品。 </span></span><span style="font-family:Calibri;font-size:10.5pt;mso-spacerun:&quot;yes&quot;;mso-bidi-font-family:&quot;Times New Roman&quot;;mso-font-kerning:1.0000pt;mso-fareast-font-family:宋體;"><br /> </span><span style="font-family:Calibri;font-size:10.5pt;mso-spacerun:&quot;yes&quot;;mso-bidi-font-family:&quot;Times New Roman&quot;;mso-font-kerning:1.0000pt;mso-fareast-font-family:宋體;"><span style="font-family:宋體;">鋼坯由某特鋼公司提供,采用電爐</span>+AOD<span style="font-family:宋體;">精煉工藝冶煉。經公司入廠複驗,管坯化學成分見表</span><span style="font-family:Calibri;">1</span><span style="font-family:宋體;">,結果表明成分符合</span><span style="font-family:Calibri;">ASME SA790</span><span style="font-family:宋體;">、</span><span style="font-family:Calibri;">ISO 13680</span><span style="font-family:宋體;">等相關產品標準要求。管坯各類夾雜物含量為</span><span style="font-family:Calibri;">0.5</span><span style="font-family:宋體;">~</span><span style="font-family:Calibri;">1.5</span><span style="font-family:宋體;">級,也符合技術條件要求,如圖</span><span style="font-family:Calibri;">1</span><span style="font-family:宋體;">所示</span></span><span style="font-family:Calibri;font-size:10.5pt;mso-spacerun:&quot;yes&quot;;mso-bidi-font-family:&quot;Times New Roman&quot;;mso-font-kerning:1.0000pt;mso-fareast-font-family:宋體;"><br /> </span><span style="font-family:Calibri;font-size:10.5pt;mso-spacerun:&quot;yes&quot;;mso-bidi-font-family:&quot;Times New Roman&quot;;mso-font-kerning:1.0000pt;mso-fareast-font-family:宋體;"><span style="font-family:宋體;">鋼坯經剝皮機剝皮後,徹底消除表麵的缺陷</span>(<span style="font-family:宋體;">氧化皮、裂紋等</span><span style="font-family:Calibri;">)</span><span style="font-family:宋體;">。根據實際要求將鋼坯進行分段、機加工,並進行尺寸公差和表麵質量檢查。管坯在加熱前進行清洗,**管坯內外表麵上的油脂和汙物,防止管坯在加熱過程中被汙染,確保管坯質量。將清洗後的管坯送入斜底式加熱爐中進行加熱到設定溫度後,送入斜軋穿孔機中進行熱穿孔,得到內外表麵質量良好、性能均勻的穿孔荒管。荒管經過固溶熱處理後進行內外表麵檢驗,為後續冷軋工藝提供合格的荒管,並為*終的成品管材提供了可靠的質量保證。穿孔荒管在周期式冷軋管機上完成冷軋變形,經過多道次冷軋,*終軋製出</span><span style="font-family:Calibri;">251mm×17mm</span><span style="font-family:宋體;">的成品鋼管,長度達</span><span style="font-family:Calibri;">10m</span><span style="font-family:宋體;">以上。 </span></span> </p> <p style="margin:0pt;"> <span style="font-family:Calibri;font-size:10.5pt;mso-spacerun:&quot;yes&quot;;mso-bidi-font-family:&quot;Times New Roman&quot;;mso-font-kerning:1.0000pt;mso-fareast-font-family:宋體;">2<span style="font-family:宋體;">、大口徑</span><span style="font-family:Calibri;">2507</span><span style="font-family:宋體;">無縫鋼管的組織與性能 </span></span> </p> <p style="margin:0pt;"> <span style="font-family:Calibri;font-size:10.5pt;mso-spacerun:&quot;yes&quot;;mso-bidi-font-family:&quot;Times New Roman&quot;;mso-font-kerning:1.0000pt;mso-fareast-font-family:宋體;">2.1 <span style="font-family:宋體;">金相組織演化</span></span><span style="font-family:Calibri;font-size:10.5pt;mso-spacerun:&quot;yes&quot;;mso-bidi-font-family:&quot;Times New Roman&quot;;mso-font-kerning:1.0000pt;mso-fareast-font-family:宋體;">&nbsp;</span><span style="font-family:Calibri;font-size:10.5pt;mso-spacerun:&quot;yes&quot;;mso-bidi-font-family:&quot;Times New Roman&quot;;mso-font-kerning:1.0000pt;mso-fareast-font-family:宋體;"><br /> </span><span style="font-family:Calibri;font-size:10.5pt;mso-spacerun:&quot;yes&quot;;mso-bidi-font-family:&quot;Times New Roman&quot;;mso-font-kerning:1.0000pt;mso-fareast-font-family:宋體;"><span style="font-family:宋體;">由於采用熱穿孔工藝進行荒管製備,穿孔工藝對荒管金相組織的影響非常顯著,特彆影響到兩相比與相組織、形態的控製。如果穿孔工藝控製不好的話,在荒管組織中容易產生金屬間相、二次奧氏體相等,進而影響到荒管質量和成品管材的性能。</span> </span><span style="font-family:Calibri;font-size:10.5pt;mso-spacerun:&quot;yes&quot;;mso-bidi-font-family:&quot;Times New Roman&quot;;mso-font-kerning:1.0000pt;mso-fareast-font-family:宋體;"><br /> </span><span style="font-family:Calibri;font-size:10.5pt;mso-spacerun:&quot;yes&quot;;mso-bidi-font-family:&quot;Times New Roman&quot;;mso-font-kerning:1.0000pt;mso-fareast-font-family:宋體;"><span style="font-family:宋體;">試驗檢驗結果表明,熱穿孔荒管金相組織較差,兩相比例不協調,並且含有較多的**相,如圖</span>2(a)<span style="font-family:宋體;">所示。特彆是,由於鋼材存在隨溫度的降低發生由韌性到脆性的轉變。一旦鋼管組織不正常,低溫</span><span style="font-family:Calibri;">(-10℃</span><span style="font-family:宋體;">~</span><span style="font-family:Calibri;">-50℃)</span><span style="font-family:宋體;">衝擊性能則大大惡化,衝擊功降低到</span><span style="font-family:Calibri;">20J</span><span style="font-family:宋體;">左右,甚至更低,此時斷口形貌為明顯的脆性斷裂特征,如圖</span><span style="font-family:Calibri;">3(a)</span><span style="font-family:宋體;">所示。因此對熱穿孔荒管及中間規格管進行合適的熱處理,調整鋼管內部組織中的兩相比例與相組成、形態。試驗結果表明,經過適當熱處理後,中間管的金相組織逐漸恢複正常,基本上未見金屬間相等出現,如圖</span><span style="font-family:Calibri;">2(b)</span><span style="font-family:宋體;">所示。低溫</span><span style="font-family:Calibri;">(-10℃</span><span style="font-family:宋體;">~</span><span style="font-family:Calibri;">-50℃)</span><span style="font-family:宋體;">衝擊性能逐漸提高到</span><span style="font-family:Calibri;">60</span><span style="font-family:宋體;">~</span><span style="font-family:Calibri;">150J</span><span style="font-family:宋體;">左右,斷口特征從脆性斷裂轉變為韌性斷裂特征,如圖</span><span style="font-family:Calibri;">3(b)</span><span style="font-family:宋體;">所示</span></span> </p> <p style="margin:0pt;"> <span style="font-family:Calibri;font-size:10.5pt;mso-spacerun:&quot;yes&quot;;mso-bidi-font-family:&quot;Times New Roman&quot;;mso-font-kerning:1.0000pt;mso-fareast-font-family:宋體;">2.2 <span style="font-family:宋體;">力學性能 </span></span><span style="font-family:Calibri;font-size:10.5pt;mso-spacerun:&quot;yes&quot;;mso-bidi-font-family:&quot;Times New Roman&quot;;mso-font-kerning:1.0000pt;mso-fareast-font-family:宋體;"><br /> </span><span style="font-family:Calibri;font-size:10.5pt;mso-spacerun:&quot;yes&quot;;mso-bidi-font-family:&quot;Times New Roman&quot;;mso-font-kerning:1.0000pt;mso-fareast-font-family:宋體;"><span style="font-family:宋體;">從成品鋼管取樣分彆進行包括金相、室溫拉伸和低溫衝擊試驗、點腐蝕性能評價試驗,以評價鋼管的使用性能及工藝性能。</span> </span><span style="font-family:Calibri;font-size:10.5pt;mso-spacerun:&quot;yes&quot;;mso-bidi-font-family:&quot;Times New Roman&quot;;mso-font-kerning:1.0000pt;mso-fareast-font-family:宋體;"><br /> </span><span style="font-family:Calibri;font-size:10.5pt;mso-spacerun:&quot;yes&quot;;mso-bidi-font-family:&quot;Times New Roman&quot;;mso-font-kerning:1.0000pt;mso-fareast-font-family:宋體;"><span style="font-family:宋體;">金相結果如圖</span>2(c)<span style="font-family:宋體;">中所示。從測試結果可以看出,成品鋼管中兩相含量比較均勻,鐵素體含量大約在</span><span style="font-family:Calibri;">45%</span><span style="font-family:宋體;">~</span><span style="font-family:Calibri;">55%</span><span style="font-family:宋體;">左右,符合相關產品標準。同時,兩相界麵清晰、過渡光滑,未見金屬間等**相。 </span></span> </p> <p style="margin:0pt;"> <span style="font-family:Calibri;font-size:10.5pt;mso-spacerun:&quot;yes&quot;;mso-bidi-font-family:&quot;Times New Roman&quot;;mso-font-kerning:1.0000pt;mso-fareast-font-family:宋體;"><span style="font-family:宋體;">對成品規格的</span>2507<span style="font-family:宋體;">管的衝擊功,進行了檢測,結果如圖</span><span style="font-family:Calibri;">4</span><span style="font-family:宋體;">所示。從圖中可以發現,無論是固溶態還是冷變形態的成品管,其衝擊性能優異。衝擊功隨著實驗溫度的降低而降低,且固溶態的衝擊功遠高於冷加工態。 </span></span><span style="font-family:Calibri;font-size:10.5pt;mso-spacerun:&quot;yes&quot;;mso-bidi-font-family:&quot;Times New Roman&quot;;mso-font-kerning:1.0000pt;mso-fareast-font-family:宋體;"><br /> </span><span style="font-family:Calibri;font-size:10.5pt;mso-spacerun:&quot;yes&quot;;mso-bidi-font-family:&quot;Times New Roman&quot;;mso-font-kerning:1.0000pt;mso-fareast-font-family:宋體;"><span style="font-family:宋體;">此外,成品管的低溫</span>(-10℃)<span style="font-family:宋體;">衝擊功均高於</span><span style="font-family:Calibri;">70J</span><span style="font-family:宋體;">。對其斷口進行觀察發現,為韌性斷裂,如圖</span><span style="font-family:Calibri;">3(b)</span><span style="font-family:宋體;">所示。 </span></span><span style="font-family:Calibri;font-size:10.5pt;mso-spacerun:&quot;yes&quot;;mso-bidi-font-family:&quot;Times New Roman&quot;;mso-font-kerning:1.0000pt;mso-fareast-font-family:宋體;"><br /> </span><span style="font-family:Calibri;font-size:10.5pt;mso-spacerun:&quot;yes&quot;;mso-bidi-font-family:&quot;Times New Roman&quot;;mso-font-kerning:1.0000pt;mso-fareast-font-family:宋體;"><span style="font-family:宋體;">采用</span>ASTM G48A<span style="font-family:宋體;">法進行了點腐蝕實驗。結果表明,點腐蝕速率小於</span><span style="font-family:Calibri;">3.0 mdd</span><span style="font-family:宋體;">。綜合金相組織、衝擊性能、室溫拉伸、點腐蝕等檢驗結果,可以發現,本次開發的大口徑</span><span style="font-family:Calibri;">2507</span><span style="font-family:宋體;">無縫鋼管性能優異,完全滿足</span><span style="font-family:Calibri;">ASMESA790</span><span style="font-family:宋體;">、</span><span style="font-family:Calibri;">ISO13680</span><span style="font-family:宋體;">標準要求。 </span></span> </p> <p style="margin:0pt;"> <span style="font-family:Calibri;font-size:10.5pt;mso-spacerun:&quot;yes&quot;;mso-bidi-font-family:&quot;Times New Roman&quot;;mso-font-kerning:1.0000pt;mso-fareast-font-family:宋體;">3<span style="font-family:宋體;">、結論 </span></span> </p> <p style="margin:0pt;"> <span style="font-family:宋體;font-size:10.5pt;mso-spacerun:&quot;yes&quot;;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family:&quot;Times New Roman&quot;;mso-font-kerning:1.0000pt;"><span style="font-family:宋體;">西安華達不鏽鋼有限公司</span></span><span style="font-family:Calibri;font-size:10.5pt;mso-spacerun:&quot;yes&quot;;mso-bidi-font-family:&quot;Times New Roman&quot;;mso-font-kerning:1.0000pt;mso-fareast-font-family:宋體;"><span style="font-family:宋體;">有限公司采用熱穿孔和冷軋工藝成功開發了規格為</span>2</span><span style="font-family:宋體;font-size:10.5pt;mso-spacerun:&quot;yes&quot;;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family:&quot;Times New Roman&quot;;mso-font-kerning:1.0000pt;">19*20</span><span style="font-family:Calibri;font-size:10.5pt;mso-spacerun:&quot;yes&quot;;mso-bidi-font-family:&quot;Times New Roman&quot;;mso-font-kerning:1.0000pt;mso-fareast-font-family:宋體;">mm<span style="font-family:宋體;">的大口徑</span><span style="font-family:Calibri;">2507</span><span style="font-family:宋體;">超級雙相無縫鋼管。大口徑</span><span style="font-family:Calibri;">2507</span><span style="font-family:宋體;">無縫鋼管金相組織、力學性能優異,符合</span><span style="font-family:Calibri;">ASME SA790</span><span style="font-family:宋體;">、狀態抗拉強度</span><span style="font-family:Calibri;">/MPa </span><span style="font-family:宋體;">屈服強度</span><span style="font-family:Calibri;">/MPa </span><span style="font-family:宋體;">延伸率</span><span style="font-family:Calibri;">/% </span><span style="font-family:宋體;">硬度</span><span style="font-family:Calibri;">/HRC</span><span style="font-family:宋體;">冷變形</span><span style="font-family:Calibri;">1060 960 27 33</span><span style="font-family:宋體;">固溶態</span><span style="font-family:Calibri;">815 580 44 25ISO13680</span><span style="font-family:宋體;">等產品標準,可用於石化、海洋、油氣開采等領域。</span></span> </p> <p style="margin:0pt;"> <span style="font-family:Calibri;font-size:10.5pt;mso-spacerun:&quot;yes&quot;;mso-bidi-font-family:&quot;Times New Roman&quot;;mso-font-kerning:1.0000pt;mso-fareast-font-family:宋體;">&nbsp;</span> </p>

西安2507/2205不鏽鋼管的組織與性能

采用熱穿孔工藝,結合多道次冷軋變形,開發出大口徑2507無縫鋼管,規格為219*20mm。結果表明:2507無縫鋼管金相組織優良,鐵素體含量約45%55%。鋼管具有良好的力學性能,低溫衝擊功可達70J以上。同時,鋼管具有較好的耐點腐蝕性能,腐蝕速率小於3.0mdd。本次開發的大口徑2507無縫鋼管化學組成、金相組織及室溫力學性能、低溫衝擊性能均滿足ASME SA790ISO 13680等產品標準要求,可以用於石化、海洋、油氣開采等領域。

超級雙相不鏽鋼(UNS 2507)由於超低碳和高鉻、高鉬、高氮的成分設計,與UNS S32205雙相不鏽鋼相比,具有更高的強度、更好的耐點腐蝕、耐應力腐蝕性能。目前主要用於各種苛刻環境,尤其是在高氯化物環境中,常用作海水熱交換器、海底油田管道纜、海水淡化等裝置。
苛刻的酸性油氣田環境中,根據介質濃度、溫度、壓力等工況,可選用的材料主要有馬氏體不鏽鋼、雙相不鏽鋼和鎳基合金等。因此,在一些高溫、高壓、高含CO2H2S環境中常采用鎳基合金材料。而在一些含CO2Cl-H2S含量較低的油氣開采環境中,2507合金由於具有冷加工硬化顯著、抗應力腐蝕性能好、耐點蝕,相對於鎳基合金油井管而言,具有價格低、性能相當等特點,綜合性能則優於馬氏體不鏽鋼。因此得到越來越廣泛的應用,應用形式主要是管材[1]-[5]
通常來講,無縫鋼管尺寸較小時,通過熱擠壓工藝或者熱穿孔工藝,結合冷軋工藝可以生產出符合要求的超級雙相無縫鋼管。但是,對於大口徑超級雙相無縫鋼管,采用熱擠壓工藝生產比較困難,特彆是管材長度要求較長時。因此,針對大口徑(外徑大於219mm)、長度較長(9m以上)等特殊需求,本公司開展了2507超級雙相無縫鋼管的研製開發,並形成了批量生產的能力。

1、大口徑2507無縫鋼管的製造流程

大口徑2507合金無縫鋼管的整個開發製造流程可以簡化為:鋼錠冶煉鍛造開坯管坯加工熱穿孔冷軋成形固溶熱處理酸洗檢驗成品。
鋼坯由某特鋼公司提供,采用電爐+AOD精煉工藝冶煉。經公司入廠複驗,管坯化學成分見表1,結果表明成分符合ASME SA790ISO 13680等相關產品標準要求。管坯各類夾雜物含量為0.51.5級,也符合技術條件要求,如圖1所示
鋼坯經剝皮機剝皮後,徹底消除表麵的缺陷(氧化皮、裂紋等)。根據實際要求將鋼坯進行分段、機加工,並進行尺寸公差和表麵質量檢查。管坯在加熱前進行清洗,**管坯內外表麵上的油脂和汙物,防止管坯在加熱過程中被汙染,確保管坯質量。將清洗後的管坯送入斜底式加熱爐中進行加熱到設定溫度後,送入斜軋穿孔機中進行熱穿孔,得到內外表麵質量良好、性能均勻的穿孔荒管。荒管經過固溶熱處理後進行內外表麵檢驗,為後續冷軋工藝提供合格的荒管,並為*終的成品管材提供了可靠的質量保證。穿孔荒管在周期式冷軋管機上完成冷軋變形,經過多道次冷軋,*終軋製出251mm×17mm的成品鋼管,長度達10m以上。

2、大口徑2507無縫鋼管的組織與性能

2.1 金相組織演化 
由於采用熱穿孔工藝進行荒管製備,穿孔工藝對荒管金相組織的影響非常顯著,特彆影響到兩相比與相組織、形態的控製。如果穿孔工藝控製不好的話,在荒管組織中容易產生金屬間相、二次奧氏體相等,進而影響到荒管質量和成品管材的性能。
試驗檢驗結果表明,熱穿孔荒管金相組織較差,兩相比例不協調,並且含有較多的**相,如圖2(a)所示。特彆是,由於鋼材存在隨溫度的降低發生由韌性到脆性的轉變。一旦鋼管組織不正常,低溫(-10℃-50℃)衝擊性能則大大惡化,衝擊功降低到20J左右,甚至更低,此時斷口形貌為明顯的脆性斷裂特征,如圖3(a)所示。因此對熱穿孔荒管及中間規格管進行合適的熱處理,調整鋼管內部組織中的兩相比例與相組成、形態。試驗結果表明,經過適當熱處理後,中間管的金相組織逐漸恢複正常,基本上未見金屬間相等出現,如圖2(b)所示。低溫(-10℃-50℃)衝擊性能逐漸提高到60150J左右,斷口特征從脆性斷裂轉變為韌性斷裂特征,如圖3(b)所示

2.2 力學性能
從成品鋼管取樣分彆進行包括金相、室溫拉伸和低溫衝擊試驗、點腐蝕性能評價試驗,以評價鋼管的使用性能及工藝性能。
金相結果如圖2(c)中所示。從測試結果可以看出,成品鋼管中兩相含量比較均勻,鐵素體含量大約在45%55%左右,符合相關產品標準。同時,兩相界麵清晰、過渡光滑,未見金屬間等**相。

對成品規格的2507管的衝擊功,進行了檢測,結果如圖4所示。從圖中可以發現,無論是固溶態還是冷變形態的成品管,其衝擊性能優異。衝擊功隨著實驗溫度的降低而降低,且固溶態的衝擊功遠高於冷加工態。
此外,成品管的低溫(-10℃)衝擊功均高於70J。對其斷口進行觀察發現,為韌性斷裂,如圖3(b)所示。
采用ASTM G48A法進行了點腐蝕實驗。結果表明,點腐蝕速率小於3.0 mdd。綜合金相組織、衝擊性能、室溫拉伸、點腐蝕等檢驗結果,可以發現,本次開發的大口徑2507無縫鋼管性能優異,完全滿足ASMESA790ISO13680標準要求。

3、結論

西安華達不鏽鋼有限公司有限公司采用熱穿孔和冷軋工藝成功開發了規格為219*20mm的大口徑2507超級雙相無縫鋼管。大口徑2507無縫鋼管金相組織、力學性能優異,符合ASME SA790、狀態抗拉強度/MPa 屈服強度/MPa 延伸率/% 硬度/HRC冷變形1060 960 27 33固溶態815 580 44 25ISO13680等產品標準,可用於石化、海洋、油氣開采等領域。

 

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