Hot rolled wire material excellent in cold forging property after spheroidizing treatment, spheroidizing-annealed steel wire having excellent cold forging property, and method for production thereof

A technology of spheroidizing annealing and manufacturing method, which is applied to hot-rolled wire rods with excellent cold forgeability after spheroidizing treatment, spheroidizing annealed steel wires with excellent cold forgeability, and their manufacturing fields, and can solve the problem of cold working. Deformation resistance becomes higher, cementite processing performance is reduced, tool life is reduced, etc., to reduce deformation resistance, hardenability and cold forging strength, and achieve the effect of processing performance.

Active Publication Date: 2008-01-02
NIPPON STEEL CORP
View PDF5 Cites 21 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0010] However, according to the technology described in Patent Document 1, although the spheroidizing annealing time can be shortened, the deformation resistance during the cold working after the spheroidizing treatment becomes high and the tool life is reduced for a single bainite structure. still can't solve the problem
[0011] In the technology described in Patent Document 2, since the structure is realized by slow cooling in the heat treatment after hot rolling, it leads to a decrease in productivity and an increase in cost
In addition, when the bainite fraction is excessive, there is also a problem

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
  • Hot rolled wire material excellent in cold forging property after spheroidizing treatment, spheroidizing-annealed steel wire having excellent cold forging property, and method for production thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0127]Steels with the compositions shown in Table 1 were subjected to wire rolling (hot rolling) under the conditions of cooling rates and constant temperature holding times in Tables 2 to 4 to produce hot-rolled steels having the structures shown in Tables 2 to 4. wire. In Table 1, steels A to E are within the scope of the invention of the present application, steel F is a sample with higher Cr and N than the range of the present application, and steel G is a sample with high Cr.

[0128] Ceq (carbon equivalent) in Tables 1 and 2 is Ceq=C%+(1 / 3)Si%+(1 / 6)Mn%. Here, C%, Si%, and Mn% in the formula represent the contents (mass %) of C, Si, and Mn in the hot-rolled wire rod, respectively.

[0129] The hot-rolled wire rod in A c1 Quickly perform spheroidizing annealing directly below the point (heating to A at a rate of 150°C / hour c1 Point directly below, at A c1 point directly below for 1 hour before air cooling).

[0130] Using a test piece (ratio of cylinder height h to di...

Embodiment 2

[0152] Steels having steel components I to V shown in Table 5 were hot-rolled under the following conditions to produce hot-rolled wire rods. After rolling, the steel is coiled at 750-1000°C. Next, cool from the upper limit temperature of 750 to 1000°C to the lower limit temperature of 400 to 550°C at a cooling rate of 20 to 100°C / sec, and keep at the constant temperature holding temperature shown in Table 6 for more than 20 seconds to complete Isothermal phase transformation, cooling to room temperature, to obtain hot-rolled wire rod.

[0153] Then, the hot-rolled wire rod is rough-drawn with the area reduction rate shown in Table 6, and spheroidized annealed (heating at a speed of 150° C. / hour to A 1 point directly below point A1, keep it for 1 hour directly below point A1, then carry out air-air cooling), and then perform fine wire drawing at the area reduction rate shown in Table 6.

[0154] table 5

[0155]

steel

Steel composition (mass%)

...

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

No PUM Login to view more

Abstract

A hot rolled wire material which comprises 0.005 to 0.6 mass % of C, and has a structure wherein pseudo-pearlite, bainite and ferrite account for 10 vol % or more, 75 vol % or less and 60 vol % or less, respectively, and the relationship that the sum of (pseudo-pearlite + bainite + ferrite) = 90 vol % is satisfied. A method for producing the above hot rolled wire material which comprises rolling a specific steel, followed by winding up at 750 to 1000 DEG C, cooling the steel from an upper limit temperature of 750 to 1000 DEG C to a lower limit temperature of 400 to 550 DEG C at a cooling rate of 20 DEG C/sec or higher, holding the steel for 20 sec or longer at 400 to 550 DEG C, and then cooling the steel. A steel wire comprises 0.005 to 0.6 mass % of C, and has a structure wherein the distances between cementite particles have a value of (standard deviation/average) of 0.50 or less. A method for producing the steel wire includes subjecting the above hot rolled wire material to spheroidizing annealing.

Description

technical field [0001] The present invention relates to shortening the spheroidizing annealing time for blanks before cold working and excellent cold workability after spheroidizing when manufacturing bolts, nuts, screws, gears, working coils, and other mechanical parts by cold working such as cold forging Hot-rolled wire rods, spheroidized annealed steel wires with excellent cold forgeability, and their manufacturing methods. [0002] This application claims priority to Japanese Patent Application No. 2005-039498 filed on February 16, 2005 and Japanese Patent Application No. 2005-137344 filed on May 10, 2005, the contents of which are incorporated herein by reference. Background technique [0003] Cold working (cold forging) can be used in a wide range of fields due to its high productivity, excellent dimensional accuracy of products, and good yield of steel products. Steel materials for such cold forging are required to have low tensile strength and high ductility (high c...

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
IPC IPC(8): C22C38/00C22C38/06C22C38/54C21D8/06
Inventor 矶新西田世纪山崎真吾加田修
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