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RU-2026112084-A - High-strength steel for chains, high-corrosion-resistant chain for mining operations and its manufacturing method

RU2026112084ARU 2026112084 ARU2026112084 ARU 2026112084ARU-2026112084-A

Inventors

  • ЧЖАО, Сысинь
  • ВАН, Чэнцюань

Assignees

  • БАОШАНЬ АЙРОН & СТИЛ КО., ЛТД.

Dates

Publication Date
20260505
Application Date
20240927
Priority Date
20230928

Claims (20)

  1. 1. Chain steel containing the following chemical elements in mass percentages: C: 0.20-0.30%, Si: 0.05-0.6%, preferably 0.15-0.6%, Mn: 1.0-1.8%, Cr: 0.4-0.8%, Ni: 0.6-1.2%, Mo: 0.5-0.9%, Ti: 0.01-0.03%, Al: 0.02-0.05%, B: 0.001-0.005%, N: 0.002-0.006%, and the balance is Fe and unavoidable impurities.
  2. 2. Steel for chains according to claim 1, the chemical composition of which satisfies the following ratio: 30000*B/(300*B+0.7*Ni+2*Cr+5*Mo)≥6, preferably 6≤30000*B/(300*B+0.7*Ni+2*Cr+5*Mo)≤24.43, where the symbols of the elements respectively represent the numerical values before the symbol % of the mass percentage content of the corresponding elements.
  3. 3. The chain steel according to claim 1, wherein the unavoidable impurities include P, S and O, where P≤0.015%, S≤0.01% and O≤0.002%.
  4. 4. The chain steel of claim 1, wherein said chain steel has a microstructure of acicular martensite.
  5. 5. Steel for chains according to item 1, having the following properties: yield strength Rp 0.2 ≥ 1050 MPa, tensile strength R m ≥ 1200 MPa, relative elongation A ≥ 14%, reduction in cross-sectional area Z ≥ 50% and Charpy impact toughness A kv at -20°C ≥ 60 J.
  6. 6. A chain comprising chain steel according to any one of claims 1 to 5 and a zinc coating applied to the chain steel.
  7. 7. The chain of claim 6, wherein the zinc coating has a thickness of 10-150 μm, preferably 40-150 μm; and/or the chain steel has a microstructure of tempered martensite and carbides dispersed interlamellarly.
  8. 8. The chain according to claim 6, wherein the chain has the following properties: yield strength Rp 0.2 ≥1050 MPa, tensile strength R m ≥1200 MPa, relative elongation A≥14%, reduction in cross-sectional area Z≥50%, Charpy impact strength A kv at -20°C≥60 J and corrosion rate ≤0.2 g/m2 ⋅h after 120 h of corrosion testing in neutral salt fog with 5% NaCl.
  9. 9. A method for manufacturing a chain according to any one of paragraphs 6-8, comprising the following stages performed sequentially:
  10. S1, melting and casting molten steel to produce a cast slab;
  11. S2, heating and rolling the cast slab, wherein the reduction of the cast slab is ≥10;
  12. S3, ring forming and welding;
  13. S4, carrying out quenching, wherein the heating temperature during quenching is 840-980°C, preferably 850-950°C, and the holding time is 1-4 hours, preferably 1-3 hours, followed by cooling with water for quenching;
  14. S5, Carrying out pre-treatment by pickling to obtain chain steel;
  15. S6, hot-dip galvanizing, in which chain steel after pickling pretreatment is subjected to a preheat treatment followed by hot-dip galvanizing to obtain a chain comprising chain steel and a zinc coating formed on the surface of the chain steel; wherein the temperature difference between the preheating temperature for the preheat treatment and the temperature of the galvanizing bath used in hot-dip galvanizing is controlled in the range of -30 to 30°C.
  16. 10. The manufacturing method according to claim 9, wherein at step S1 the melting comprises melting in an electric furnace or converter, refining in a ladle furnace and vacuum degassing or circulating vacuuming, a continuous casting process is used for casting; preferably, vacuum degassing or circulating vacuuming is carried out for 10-20 minutes; during casting, the degree of superheating of the molten steel in the pouring ladle is controlled in the range of 15-40°C;
  17. and/or in the S2 stage, during heating and rolling, the cast slab is heated at a heating temperature of ≥1150°C for 3-6 hours, and the final rolling temperature is ≥850°C; after rolling, air cooling or slow cooling is carried out;
  18. and/or at step S6, the preheating temperature is 400-550°C, and the preheating time is ≥0.5 h; the temperature of the galvanizing bath used in hot-dip galvanizing is 400-530°C.
  19. 11. The manufacturing method according to claim 9, wherein the zinc coating has a thickness of 10-150 μm, preferably 40-150 μm.
  20. 12. The manufacturing method according to claim 9, wherein the chain steel obtained in step S6 has a microstructure of tempered martensite and carbides dispersed interlamellarly.