Cast iron is an iron-carbon alloy with a mass fraction of carbon greater than 2.11%. Cast iron is obtained by remelting pig iron in the furnace, adding ferroalloy, scrap steel, and returning to the furnace to adjust the composition. Grey cast iron and ductile iron are the two most widely used cast irons for producing castings.
China's cast iron grades are mainly expressed and distinguished by mechanical properties. The first set of numbers in the grade indicates the minimum tensile strength (in MPa), and the second set of numbers (if any) indicates the minimum elongation at break (%). The two sets of numbers are separated by a dash "-".
The English letter code of gray cast iron is HT, where H is the first letter of the Chinese Pinyin (Hui Se) meaning gray; T is the first letter of the Chinese Pinyin (Tie) of iron. The numbers in China's grey iron grades indicate the minimum tensile strength (MPa). For example, HT250 represents gray cast iron with a minimum tensile strength of 250 MPa.
| Comparison of Grey Cast Iron from Different Countries | ||||||||||
| No. | China | Japan | U.S.A. | ISO | Germany | France | Russia | U.K. | ||
| GB | JIS | ASTM | UNS | DIN | W-Nr. | NF EN | гост | BS | ||
| 1 | HT100 | FC100 | GG10 | 0.6010 | EN-GJL-100 | гч10 | Grade 100 | |||
| 2 | HT150 | FC150 | 150/~No.20 | F11401 | ISO 185/JL/150 | GG15 | 0.6015 | EN-GJL-150 | гч15 | Grade 150 |
| 3 | HT200 | FC200 | 200/~No.30 | F12101 | ISO 185/JL/200 | GG20 | 0.6020 | EN-GJL-200 | гч18 гч20 гч21 | Grade 180 Grade 220 |
| 4 | HT250 | FC250 | 250/~No.35 | F12401 | ISO 185/JL/250 | GG25 | 0.6025 | EN-GJL-250 | гч24 гч25 | Grade 260 |
| 5 | HT300 | FC300 | 300/~No.45 | F13101 | ISO 185/JL/300 | GG30 | 0.6030 | EN-GJL-300 | гч30 | Grade 300 |
| 6 | HT350 | FC350 | 350/~No.50 | F13501 | ISO 185/JL/350 | GG35 | 0.6035 | EN-GJL-350 | гч35 | Grade 350 |
The English letter code of ductile iron is QT, where Q is the first letter of the Chinese Pinyin (Qiumo) of Chinese spheroidal graphite; T is the first letter of the Chinese Pinyin (Tie) of iron. There are two sets of numbers in China's ductile iron grades. The first set of numbers represents the minimum tensile strength (MPa), and the second set of numbers represents the elongation after fracture (%). The two sets of numbers are separated by a dash "-". For example, QT400-18 represents a ductile iron with a minimum tensile strength of 480 MPa and a minimum elongation of 18%.
| Ductile Iron Grade from Different Countries | ||||||||||
| No. | China | Japan | U.S.A. | ISO | German | France | Russia гост | U.K. BS | ||
| GB | JIS | ASTM | UNS | DIN | W-Nr. | NF | ||||
| 1 | FCD350-22 | - | - | 350-22 | - | - | - | Bч35 | 350/22 | |
| 2 | QT400-15 | FCD400-15 | - | - | 400-15 | GGG-40 | 0.7040 | EN-GJS-400-15 | Bч40 | 370/17 |
| 3 | QT400-18 | FCD400-18 | 60-40-18 | F32800 | 400-18 | - | - | EN-GJS-400-18 | - | 400/18 |
| 4 | QT450-10 | FCD450-10 | 65-45-12 | F33100 | 450-10 | - | - | EN-GJS-450-10 | Bч45 | 450/10 |
| 5 | QT500-7 | FCD500-7 | 80-55-6 | F33800 | 500-7 | GGG-50 | 0.7050 | EN-GJS-500-7 | Bч50 | 500/7 |
| 6 | QT600-3 | FCD600-3 | ≈80-55-06 ≈100-70-03 | F3300 F34800 | 600-3 | GGG-60 | 0.7060 | EN-GJS-600-3 | Bч60 | 600/3 |
| 7 | QT700-2 | FCD700-2 | 100-70-03 | F34800 | 700-2 | GGG-70 | 0.7070 | EN-GJS-700-2 | Bч70 | 700/2 |
| 8 | QT800-2 | FCD800-2 | 120-90-02 | F36200 | 800-2 | GGG-80 | 0.7080 | EN-GJS-800-2 | Bч80 | 800/2 |
| 8 | QT900-2 | 120-90-02 | F36200 | 800-2 | GGG-80 | 0.7080 | EN-GJS-900-2 | ≈Bч100 | 900/2 | |
| Gray Iron Comparison | Microstructure（Volume Fractions）（％） | |||
| China（GB/T 9439) | ISO 185 | ASTM A48/A48M | EN 1561 | Matrix Structure |
| HT100 (HT10-26) | 100 | No.20 F11401 | EN-GJL-100 | Pearlite: 30-70％, coarse flakes; Ferrite: 30-70％; Binary Phosphorus Eutectic: ＜7％ |
| HT150 (HT15-33) | 150 | No.25A F11701 | EN-GJL-150 | Pearlite: 40-90％, medium coarse flakes; Ferrite: 10-60％; Binary Phosphorus Eutectic:＜7％ |
| HT200 (HT20-40) | 200 | No.30A F12101 | EN-GJL-200 | Pearlite: ＞95％, medium flakes; Ferrite＜5％; Binary Phosphorus Eutectic＜4％ |
| HT250 (HT25-47) | 250 | No.35A F12401 No.40A F12801 | EN-GJL-250 | Pearlite: ＞98％ medium thin flakes; Binary Phosphorus Eutectic:＜2％ |
| HT300 (HT30-54) | 300 | No.45A F13301 | EN-GJL-300 | Pearlite: ＞98％ medium thin flakes; Binary Phosphorus Eutectic:＜2％ |
| HT350 (HT35-61) | 350 | No.50A F13501 | EN-GJL-350 | Pearlite: ＞98％ medium thin flakes; Binary Phosphorus Eutectic:＜1％ |
| Ductile Iron Comparison | Chemical Composition（％） | Matrix Structure | |||||||||
| GB/T 1348-1988 | ASTM A536-84(2004) | EN 1563:-1997 | C | Si | Mn | P | S | Mg | Re | others | |
| QT400-18 | 60-40-18① F32800 | GJS-400-18 JS1020 | 3.6-3.8 | 2.3-2.7 | ＜0.5 | ＜0.08 | ＜0.025 | 0.03-0.05 | 0.02-0.03 | — | Annealed Ferrite |
| QT400-15 | 60-42-10 F32900 | GJS-400-15 JS1030 | 3.5-3.6 | 3.0-3.2 | ＜0.5 | ＜0.07 | ＜0.02 | 0.04 | 0.02 | — | Annealed Ferrite |
| QT450-10 | 65-45-12 F33100 | GJS-450-10 JS1040 | 3.4-3.9 | 2.7-3.0 | 0.2-0.5 | ＜0.07 | ＜0.03 | 0.06-0.1 | 0.03-0.1 | — | Annealed Ferrite |
| QT500-7 | 70-50-05 | GJS-500-7 JS1050 | 3.6-3.8 | 2.5-2.9 | ＜0.6 | ＜0.08 | ＜0.025 | 0.03-0.05 | 0.03-0.05 | — | Pearlite + Ferrite |
| QT600-3 | 80-60-03② F34100 | GJS-600-3 JS1060 | 3.6-3.8 | 2.0-2.4 | 0.5-0.7 | ＜0.08 | ＜0.025 | 0.035-0.05 | 0.025-0.045 | — | Normalized Pearlite |
| QT700-2 | 100-70-03 F34800 | GJS-700-2 JS1070 | 3.7-4.0 | 2.3-2.6 | 0.5-0.8 | ＜0.08 | ＜0.02 | 0.035-0.065 | 0.035-0.065 | Mo0.15-0.4 Cu0.4-0.8 | Mix Microstructure |
| QT800-2 | - | GJS-800-2 JS1080 | 3.7-4.0 | ＜2.5 | ＜0.5 | ＜0.07 | ＜0.03 | — | — | Mo0.39 Cu0.82 | Mix Microstructure |
| QT900-2 | 120-90-02 F36200 | GJS-900-2 JS1090 | 3.5-3.7 | 2.7-3.0 | ＜0.5 | ＜0.08 | ＜0.025 | 0.03-0.05 | 0.025-0.045 | Mo0.15-0.25 Cu0.5-0.7 | Lower Bainite |
| ① from ASTM A716-2003. ② from ASTM A476/A476M-2000。 | |||||||||||
Post time: Aug-13-2022