Y. L . asked in 科學工程學 · 1 decade ago

材料科學選擇題我需要答案和解釋

1. Which of the steels below falls within the low-carbon steel classification:

(A) AISI 1040, (B) AISI1080 (C) AISI 304, (D) AISI 4310, or (E) AISI 4340.

2. The predominant alloying element in stainless steel is (A) C, (B) Cr, (C) Cu, (D) Co, (E) Cl.

3. The low carbon steels are relatively soft and weak compared with other steels because the

microstructures in low-carbon steels consist of (two corrected answers) (A) austenite (B) cemetite (C)ferrite (D) martensite, or (E) pearlite.

4. Which of the microstructure in carbon steels has the highest strength? (A) bainite, (B) coarse pearlite,(C) fine pearlite, (D) martensite, or (E) spherodite.

1 Answer

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  • user
    Lv 4
    1 decade ago
    Favorite Answer

    1.(D)4310含碳量0.10%

    2.(B) Cr 含鉻為主要成分

    3.(C、E)肥粒鐵+波來鐵

    4.(A、D)變韌鐵+麻田散鐵

    首先(850~750C)在晶界析出鐵素體肥粒鐵F薄膜, 再來依次出現珠光體波來鐵P(~650),貝氏體 變韌鐵B(400~300C)與馬氏體麻田散鐵(<200C). 淬火目的在獲得~100%麻田散鐵. 冷速不足則生出其他"非馬氏體麻田散鐵(non-martensitic)組織, 硬度差異不大, 但大幅降低強度韌性. 想像強韌的M晶粒, 被毫無強度的F隔開 受壓力狀態時表現差異不大, 處拉應力狀態下, 則立顯脆弱.

    有此學生,夫復何求!!唉

    天命苟如此,且進杯中物阿

    2009-06-14 21:27:29 補充:

    Cr是最主要的成分

    因為氧化快,很快就再金屬表面形成一層薄膜,而不再繼續向下氧化,使其達到防銹功能。

    後面兩個,請參考機械材料裡面的資料或上面那個網站!!

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