Steel for case hardening which has excellent cold workability and machinability and which exhibits excellent fatigue characteristics after carburizing and quenching, and process for production of same

A technology of carburizing and quenching and cold workability, which is applied in the direction of metal material coating process, coating, solid-state diffusion coating, etc., can solve the problems of increased manufacturing costs, achieve extended life, excellent processability, and suppress the coarseness of grains effect

Active Publication Date: 2012-03-14
NIPPON STEEL CORP
View PDF5 Cites 21 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, if annealing is performed, there is a problem that the manufacturing cost increases

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Steel for case hardening which has excellent cold workability and machinability and which exhibits excellent fatigue characteristics after carburizing and quenching, and process for production of same
  • Steel for case hardening which has excellent cold workability and machinability and which exhibits excellent fatigue characteristics after carburizing and quenching, and process for production of same
  • Steel for case hardening which has excellent cold workability and machinability and which exhibits excellent fatigue characteristics after carburizing and quenching, and process for production of same

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0165] Steels having the compositions shown in Tables 1 to 3 were smelted and cast at a solidification cooling rate of 10 to 11° C. / min. The blank columns of the components in Tables 1 to 3 indicate that they are not intentionally added, and the underlines indicate that they are outside the scope of the present invention.

[0166] The solidification cooling rate is adjusted based on data obtained by sorting out the relationship between the cooling conditions and the solidification cooling rate when casting slabs of various sizes in advance. The solidification cooling rate of a part of the slab was confirmed to be in the range of 10 to 11° C. / min from the secondary dendrite arm spacing. Part of the slab is subjected to slab rolling as needed.

[0167]

[0168]

[0169]

[0170] Then hot working is carried out to manufacture bar steel with a diameter of 24-30mm. The microscopic observation of the bar steel was carried out, and the measurement of the bainite fraction was...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

PUM

PropertyMeasurementUnit
diameteraaaaaaaaaa
diameteraaaaaaaaaa
Login to view more

Abstract

Provided is a steel for case hardening, which is to be subjected to cold working, machining, and carburizing and quenching, and in which the occurrence of coarse particles is prevented. The steel for case hardening has excellent cold workability and machinability and further exhibits excellent fatigue characteristics after carburizing and quenching. The steel for case hardening is characterized by: containing, by mass, 0.001 to 0.15% of S, 0.05 to 0.2% of Ti, at most 0.04% of Al, at most 0.0050% of N, and specific amounts of other specific components, and further containing at most 0.003% of Mg, and / or at most 0.01% of Zr, and / or at most 0.005% of Ca; having a content of precipitated AlN of 0.01% or less; and satisfying the relationship: d = 1700[S]+20 [wherein d is the density (particles / mm2) of sulfides which have equivalent circle diameters exceeding 20[mu]m and aspect ratios exceeding 3; and [S] is the content (mass%) of S].

Description

technical field [0001] The present invention relates to a case-hardened steel produced by hot working such as hot rolling or hot forging, and subjected to carburizing and quenching after cold forging, roll forming or cutting, and a production method thereof. Background technique [0002] Rotating parts such as gears and bearings, constant velocity universal joints, and rotation transmission parts such as shafts require surface hardness, so carburizing and quenching are performed. These carburized parts are, for example, made of medium-carbon alloy steel for machine structures specified in JIS G4052, JIS G 4104, JIS G 4105, JIS G 4106, etc., and plastically processed by hot forging, medium temperature forging, cold forging, roll forming, etc. Or it can be manufactured by cutting into a predetermined shape and then carburizing and quenching. [0003] When manufacturing a carburized part, the shape accuracy of the part may deteriorate due to heat treatment strain caused by car...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

Application Information

Patent Timeline
no application Login to view more
Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/00C21D8/06C22C38/60C21D1/06
CPCC21D1/06C21D8/0226C22C1/02C23C8/32C23C8/80C22C38/04C22C38/48C22C38/001C22C38/46C22C38/26C22C38/24C22C38/06C22C38/22C22C38/32C22C38/38C22C38/002C22C38/28C22C38/02C22C1/11C22C38/00
Inventor 桥村雅之宫西庆小泽修司久保田学越智达朗
Owner NIPPON STEEL CORP
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Try Eureka
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap