[Q&A Question 176] 2018.06.30
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【Q&A Question 176】June 30, 2018: Briefly describe the properties of the materials used for furnace tubes in heating furnaces ? Reference answer: ① Creep limit ； ②Durable strength ； ③temper brittleness ； ④thermal brittleness ； ⑤Spheroidization of pearlite ； ⑥Graphitization. (Unless otherwise specified, all questions and answers are based on hydrogenation units.) ) Correct: 3 wealth, Incorrect: 1 wealth ； Mass posting of posts – rated based on the lowest score ； Replies that are unrelated to the answer are considered spam and will be deleted immediately. For management purposes, if you need to view content from a few days ago, please go to https://bbs.hcbbs.com/home.php?mod=space&uid=3862647&do=thread&view=me&from=space through the summary post below. The APP short-video skills competition has started! https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=1951670
①creep limit； ②Durable strength ； ③temper brittleness ；
The material of the heating furnace tubes is stainless steel, which features excellent resistance to intergranular corrosion; it also demonstrates good corrosion resistance in solutions such as acids, alkalis, and salts. Taking TP347 as an example: TP347 stainless steel pipes are characterized by their excellent resistance to intergranular corrosion; they also exhibit good corrosion resistance in acids, alkalis, salts, and other solutions. Physical constants of TP347 stainless steel tubes:
Melting point: 1398–1427°C
Density: 7.9 g/cm³
Specific heat capacity: 500 J/(kg·K)
Elastic modulus: 196 GPa at 20°C, 186 GPa at 200°C, 177 GPa at 400°C, 167 GPa at 500°C, 167 GPa at 600°C
Specific resistivity: 0.75 nN·m
Chemical composition of TP347 stainless steel tubes:
C: ≤0.10, Si: ≤1.00, Mn: ≤2.00, Cr: 17.0–20.0, Ni: 9.0–13.0, Nb: 8×C% – 1.5, S: ≤0.030, P: ≤0.035
Mechanical properties of TP347 stainless steel tubes:
At 20°C: 559–637, 235–274, 53–61, 63–69, 20.6–27.4
At 500°C: 392–429, 147–216, 28–36, 56–66, 23.5–28.4
At 600°C: 363–382, 137–186, 28–34, 54–65, 24.5–30.4
At 650°C: 304–363, 118–167, 31–38, 54–61, 23.5–31.4
At 700°C: 245–304, 31–42, 44–60, 24.5–29.4
Heat treatment for TP347 stainless steel tubes: Solution treatment at 1000–1100°C, followed by water quenching.
Corrosion resistance of TP347 stainless steel tubes:
Intergranular corrosion: Tested using the copper sulfate plus sulfuric acid plus copper scrap method (T method), the copper sulfate plus sulfuric acid method (L method), and the 65% HNO₃ method (X method).
Oxidation resistance: At temperatures of 750–800°C in air, this steel exhibits stable oxidation resistance
Melting point: 1398–1427°C
Density: 7.9 g/cm³
Specific heat capacity: 500 J/(kg·K)
Elastic modulus: 196 GPa at 20°C, 186 GPa at 200°C, 177 GPa at 400°C, 167 GPa at 500°C, 167 GPa at 600°C
Specific resistivity: 0.75 nN·m
Chemical composition of TP347 stainless steel tubes:
C: ≤0.10, Si: ≤1.00, Mn: ≤2.00, Cr: 17.0–20.0, Ni: 9.0–13.0, Nb: 8×C% – 1.5, S: ≤0.030, P: ≤0.035
Mechanical properties of TP347 stainless steel tubes:
At 20°C: 559–637, 235–274, 53–61, 63–69, 20.6–27.4
At 500°C: 392–429, 147–216, 28–36, 56–66, 23.5–28.4
At 600°C: 363–382, 137–186, 28–34, 54–65, 24.5–30.4
At 650°C: 304–363, 118–167, 31–38, 54–61, 23.5–31.4
At 700°C: 245–304, 31–42, 44–60, 24.5–29.4
Heat treatment for TP347 stainless steel tubes: Solution treatment at 1000–1100°C, followed by water quenching.
Corrosion resistance of TP347 stainless steel tubes:
Intergranular corrosion: Tested using the copper sulfate plus sulfuric acid plus copper scrap method (T method), the copper sulfate plus sulfuric acid method (L method), and the 65% HNO₃ method (X method).
Oxidation resistance: At temperatures of 750–800°C in air, this steel exhibits stable oxidation resistance
AL-6XN,Cr5Mo
High-temperature resistance, corrosion resistance, oxidation resistance
Heat resistance, corrosion resistance, oxidation resistance, etc.
①creep limit； ②Durable strength ； ③temper brittleness ； ④thermal brittleness ； ⑤Spheroidization of pearlite ； ⑥Graphitization.
①creep limit； ②Durable strength ； ③temper brittleness ；
High-temperature resistance, corrosion resistance, oxidation resistance
Heat resistance, corrosion resistance, oxidation resistance, etc.
①creep limit； ②Durable strength ； ③temper brittleness