Steel for large-sized wind power fastener and manufacturing method of steel

A technology for large-scale fasteners, applied in the manufacture of tools, metal rolling, temperature control, etc., can solve the problems of inconsistency in area shrinkage of finished products, increase of post-finishing pressure, poor low-temperature impact performance, etc., and achieve hardness differences small effect

CN110643881AActive Publication Date: 2020-01-03NANJING IRON & STEEL CO LTD
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2020-01-03

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Abstract

The invention discloses steel for a large-sized wind power fastener. The steel is prepared from the element components in percentage by mass: 0.38-0.45% of C, 0.20-0.35% of Si, 0.60-0.80% of Mn, lessthan or equal to 0.015% of P, less than or equal to 0.010% of S, 0.95-1.20% of Cr, 0.18-0.30% of Mo, 0.10-0.25% of Ni, 0.02-0.08% of Nb, 0.020-0.050% of Al, less than or equal to 0.008% of N, and thebalance of Fe and inevitable impurities. After heat treatment, the core part of the steel is provided with 90% or above of a martensitic structure, the surface hardness difference of the core part isless, especially the low-temperature impact property is excellent, the good mechanical properties are achieved, the tensile property meets the 10.9-grade strength requirements, and the machining usingrequirements for the steel for 48-65 mm of the large-sized wind power fastener by a user can be met.
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Description

technical field

[0001] The invention relates to a steel for fasteners and a manufacturing method thereof, in particular to a steel for large-scale wind power fasteners and a manufacturing method thereof. Background technique

[0002] At present, wind power has made great progress in the context of building a resource-saving and environment-friendly society. With the high performance of wind turbines, the increase of material application stress, the reduction of the size of the main engine and the lightweight of the gearbox, higher design stress and weight reduction requirements for bolts are put forward, and the most effective measures to meet this requirement are Improve the service strength of steel for bolts. The service conditions of wind turbines are harsh, and they are subjected to extreme heat and cold and extreme temperature differences all year round. of toughness.

[0003] The stability of mechanical properties of wind power bolts is mainly restricted by the har...

Examples

Embodiment Construction

[0052] The element composition of the present invention contains: C: 0.38-0.45%, Si: 0.20-0.35%, Mn: 0.60-0.80%, P≤0.015%, S≤0.010%, Cr: 0.95-1.20%, Mo : 0.18-0.30%, Ni: 0.10-0.25%, Nb: 0.02-0.08%, Al: 0.020-0.050%, N≤0.008%, the balance is Fe and unavoidable impurities; Permeability formula:

[0053]

[0054] in:

[0055]

[0056] D. i =25.4×(0.171+0.001×C+0.265×C 2 )×(1.000+3.333×Mn)×(1.000+0.700×Si)×(1.000+0.363×Ni)×(1.000+2.160×Cr)×(1.000+3.000×Mo)×(1.000+0.365×Cu)

[0057] b=0.22Di-0.34

[0058] In the formula, x is the end quenching distance, the hardness distribution is J(x), C is the carbon content, Di is the depth from the end to the half martensite (50% martensite), b is the end to the full martensite The depth of the body (100% martensite).

[0059] In order to verify that the limited range of each element in the present invention can achieve technical effects, according to the above element composition requirements, 6 furnaces of the steel for wind powe...