本文關(guān)鍵詞： 低碳微合金鋼 腐蝕 組織 力學(xué)化學(xué)效應(yīng)　出處：《北京科技大學(xué)》2015年博士論文　論文類型：學(xué)位論文

【摘要】：低碳微合金耐候鋼具有較好的力學(xué)性能、耐蝕性和經(jīng)濟的生產(chǎn)成本等特點,作為結(jié)構(gòu)鋼的一種,一般都要承受一定應(yīng)力,并在一定腐蝕環(huán)境中服役,因而,既要考慮其力學(xué)性能,又要考慮其腐蝕行為,即外加應(yīng)力作用時的腐蝕行為——力學(xué)化學(xué)效應(yīng)。目前關(guān)于力學(xué)化學(xué)效應(yīng)的研究還不夠完善且存在一定的問題,關(guān)于材料組織對力學(xué)化學(xué)效應(yīng)的影響還未見報道。因此,本論文設(shè)計了一種低碳微合金耐候鋼,通過熱處理得到成分相同的三種不同顯微組織：貝氏體組織(B)、鐵素體貝氏體組織(FBDP)、鐵素體珠光體組織(FPDP),并以具有這三種不同顯微組織的低碳微合金鋼為研究對象,對其力學(xué)化學(xué)效應(yīng)機理進行了研究。本研究對于發(fā)展高性能耐候鋼、預(yù)測材料的服役安全和指導(dǎo)工程選材有重要意義。 通過研究無外加應(yīng)力作用時組織對低碳微合金鋼腐蝕行為的影響發(fā)現(xiàn),顯微組織的改變可以影響材料整體的熱力學(xué)穩(wěn)定性：B鋼的熱力學(xué)穩(wěn)定性最高FPDP鋼的次之,FBDP鋼的最差；三種不同相的熱力學(xué)穩(wěn)定性順序也各不相同：P的熱力學(xué)穩(wěn)定性最高,B的次之,F的最差。B鋼屬于均勻腐蝕,其腐蝕表面粗糙度最��；FBDP鋼和FPDP鋼屬于擇優(yōu)腐蝕,FPDP鋼的表面粗糙度大于FBDP鋼的表面粗糙度。顯微組織對低碳微合金鋼長期的腐蝕速率沒有明顯影響。 FBDP鋼在3.5mass%NaCl溶液中的浸泡初期,腐蝕優(yōu)先在鐵素體內(nèi)部及鐵素體晶界處開始,鐵素體相作為電偶腐蝕陽極比貝氏體更加容易腐蝕。FBDP鋼腐蝕表面的表面粗糙度主要是由兩相的擇優(yōu)腐蝕造成的,其大小決定于其顯微組織中各相的體積分?jǐn)?shù)及兩相的高度差。本論文提出了一種可靠的腐蝕模型用于描述多相鋼中各相的腐蝕行為,并利用參數(shù)KG對雙相鋼中兩相間的電偶腐蝕行為進行評價。研究表明,造成FBDP鋼中貝氏體組織(BFBDP)伏打電位(自腐蝕電位)較高、耐腐蝕性能較好的原因是由于C元素在BFBDP中的富集。 在外加彈性應(yīng)力作用時,B鋼、FBDP鋼對力學(xué)化學(xué)效應(yīng)不敏感；FPDP鋼的力學(xué)化學(xué)效應(yīng)最顯著且隨外加應(yīng)力的增大而增大。低碳微合金鋼在0.5mass%NaCl溶液中浸泡時,其腐蝕過程的電化學(xué)反應(yīng)機理、腐蝕產(chǎn)物膜的成分和物相及其生成過程不受材料的顯微組織及外加應(yīng)力的影響。在外加彈性應(yīng)力作用下,B鋼的自腐蝕電位變化不明顯,FPDP鋼的自腐蝕電位會隨著外加彈性應(yīng)力的增大而負(fù)移。腐蝕產(chǎn)物膜的破裂是造成低碳微合金鋼力學(xué)化學(xué)效應(yīng)的本質(zhì)原因。腐蝕產(chǎn)物膜的破裂與試樣表面的蠕變、試樣內(nèi)部不均勻蠕變行為有關(guān),當(dāng)試樣應(yīng)(蠕)變導(dǎo)致的試樣表面積的增大量大于新生腐蝕產(chǎn)物膜對新增表面的覆蓋量時,試樣表面的腐蝕產(chǎn)物膜將出現(xiàn)開裂現(xiàn)象。 隨著外加彈性應(yīng)力的增加,FPDP鋼中珠光體組織(PFPDP)的腐蝕速率先增大后減小。應(yīng)力對FPDP鋼腐蝕過程中腐蝕溶質(zhì)的擴散過程及FPDP鋼中兩相的電偶腐蝕的影響共同決定了FPDP鋼中兩相的力學(xué)化學(xué)效應(yīng)。在外加應(yīng)力作用下FPDP鋼中兩相的伏打電位差會增加,導(dǎo)致兩相的電偶腐蝕趨勢增大,腐蝕表面的粗糙度也隨之增大。
[Abstract]:Good mechanical properties of low carbon microalloyed steel, corrosion resistance and economic cost, as a kind of structural steel, usually under stress, and service, and in a certain corrosive environment, should not only consider the mechanical properties, but also consider the corrosion behavior, which should be applied: effect of mechanical and chemical corrosion behavior of force. The current research on the mechanochemical effect is still not perfect and there are some problems about the influence of microstructure on the mechanical and chemical effect has not been reported. Therefore, this paper designed a kind of low carbon micro alloy steel, three different microstructures of the same composition by heat treatment: bainite (B), ferrite bainite (FBDP), ferrite pearlite (FPDP), and with the low carbon has three different microstructures of microalloyed steel as the research object, the mechanics and chemistry This study is of great significance for the development of high performance weathering steel, the prediction of the service safety of the materials and the guidance of the material selection.
By studying the effects of no external stresses on Microstructure of low carbon microalloyed steel corrosion behavior, microstructure change can affect the thermodynamic stability of the whole material: the highest FPDP steel B steel the thermodynamic stability of FBDP steel is the worst; three kinds of different thermal phase stability order is also different P: the thermodynamic stability is the highest, the second is B, F is the worst.B steel is uniform corrosion, the corrosion of the minimum surface roughness; FBDP steel and FPDP steel is preferred corrosion, FPDP steel surface rough surface degree of roughness was higher than that of FBDP steel. The microstructure of low carbon microalloyed steel for corrosion the rate has no obvious influence.
The early immersion of FBDP steel in 3.5mass%NaCl solution, corrosion preferentially in the ferrite and ferrite grain boundaries, ferrite phase as the anode surface galvanic corrosion Bibeishi body more prone to corrosion corrosion of.FBDP steel surface roughness is mainly caused by the preferential etching phase, the height difference of which depends on the volume fraction and the two phase of each phase in the microstructure. This paper proposes a reliable corrosion model is used to describe the corrosion behavior of each phase of the multiphase steel, evaluated by the KG parameters of the galvanic corrosion behavior of two phases in dual phase steels. The research shows that resulted in FBDP steel bainite (BFBDP) potential (Ecorr) high resistance to corrosion, good performance is due to the enrichment of BFBDP in the C element.
The external elastic stress, B steel, FBDP steel is not sensitive to chemical mechanical effect; increasing effect of mechanical and chemical FPDP steel is the most significant and with applied stress increases. Low carbon microalloyed steel immersed in 0.5mass%NaCl solution, the electrochemical reaction mechanism of the corrosion process, corrosion products and components the membrane phase and its formation process is not affected by the microstructure of the material and applied stress. The external elastic stress of B steel, the corrosion potential did not change significantly, the corrosion potential of FPDP steel will increase along with the elastic stress and negative shift. Rupture of corrosion products film is the essential reason due to the low carbon microalloyed steel. The effect of mechanical and chemical corrosion product film rupture and surface creep, the creep behavior of specimen is not uniform, when the specimen should be changed to sample (creep) surface area increases the corrosion product film is higher than that of the new freshmen When the surface coverage is increased, the corrosion product film on the surface of the specimen will appear cracking.
With the increase of the external elastic stress of pearlite in steel FPDP (PFPDP) the corrosion rate increased firstly and then decreased. Effects of galvanic corrosion of two-phase force diffusion process and FPDP steel on Corrosion of FPDP steel corrosion in the process of solute in determines the effect of mechanical and chemical phase in FPDP steel. In the external phase V in FPDP steel under the force of potential difference will increase, resulting in the increase of galvanic corrosion tendency of two-phase corrosion, the surface roughness increases.

【學(xué)位授予單位】：北京科技大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2015
【分類號】：TG142.1

【參考文獻】

相關(guān)期刊論文 前10條

1 李少坡;郭佳;楊善武;賀信萊;;碳含量和組織類型對低合金鋼耐蝕性的影響[J];北京科技大學(xué)學(xué)報;2008年01期

2 張全成,吳建生,鄭文龍,王建軍,陳家光,李愛柏,楊曉芳;合金元素的二次分配對耐候鋼抗大氣腐蝕性能的影響[J];材料保護;2001年04期

3 陳小平,王向東,江社明,李春艷;晶粒尺寸對耐候鋼抗大氣腐蝕性能的影響[J];材料保護;2005年07期

4 董杰;崔文芳;張思勛;劉春明;;CuPCr鋼顯微組織對全浸海水腐蝕行為的影響[J];東北大學(xué)學(xué)報(自然科學(xué)版);2007年09期

5 閆建中,吳蔭順,李久青,張琳;316L不銹鋼微動磨蝕過程力學(xué)化學(xué)交互作用研究[J];腐蝕科學(xué)與防護技術(shù);2000年05期

6 張全成,吳建生,鄭文龍,王建軍,陳家光,楊曉芳,李愛柏;耐候鋼表面穩(wěn)定銹層形成機理的研究[J];腐蝕科學(xué)與防護技術(shù);2001年03期

7 劉麗宏,齊慧濱,盧燕平,李曉剛;耐大氣腐蝕鋼的研究概況[J];腐蝕科學(xué)與防護技術(shù);2003年02期

8 牛林,張長橋,林海潮;彈、塑性應(yīng)變對奧氏體不銹鋼AISI321電化學(xué)行為的影響[J];腐蝕科學(xué)與防護技術(shù);2003年04期

9 王景茹;朱立群;張崢;;靜載荷對30CrMnSiA在中性及酸性溶液中腐蝕速度的影響[J];腐蝕科學(xué)與防護技術(shù);2008年04期

10 安英輝;董超芳;肖葵;李曉剛;;Kelvin探針測量技術(shù)在電化學(xué)研究中的應(yīng)用進展[J];腐蝕科學(xué)與防護技術(shù);2008年06期

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