Unlock instant, AI-driven research and patent intelligence for your innovation.

Wire rod having superior hydrogen delayed fracture resistance, method for manufacturing same, high strength bolt using same and method for manufacturing bolt

A delayed fracture and wire technology, applied in the direction of manufacturing tools, furnace types, furnaces, etc., can solve the problems of inability to guarantee price competitiveness, high manufacturing costs, and decreased delayed fracture, and achieve excellent resistance to hydrogen-induced delayed fracture, low Manufacturing cost, effect of achieving compactness

Inactive Publication Date: 2014-03-19
POHANG IRON & STEEL CO LTD
View PDF3 Cites 1 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] However, most of the domestic and foreign designed inventions have disadvantages such as high manufacturing costs and thus complicated processes required, and require extremely precise rolling and cooling conditions when making steel
Therefore, the technology suffers from disadvantages such as high manufacturing cost and complicated process, and has limitations such as extremely precise rolling and cooling conditions required to manufacture steel
However, since the technique is mainly aimed at improving hydrogen-induced delayed fracture resistance by adding a large amount of molybdenum (Mo), it may be disadvantageous in terms of high manufacturing cost
[0011] As mentioned above, compared with the increase in tensile strength of heat-treated and non-heat-treated carbon steels (tensile strength above 1200MPa), the limitation of the decrease in resistance to hydrogen-induced delayed fracture has not been resolved, due to the addition of expensive alloying elements, which may Price competitiveness cannot be guaranteed, in particular, the stable guarantee of data on delayed fracture properties caused by hydrogen may be flawed

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
  • Wire rod having superior hydrogen delayed fracture resistance, method for manufacturing same, high strength bolt using same and method for manufacturing bolt
  • Wire rod having superior hydrogen delayed fracture resistance, method for manufacturing same, high strength bolt using same and method for manufacturing bolt
  • Wire rod having superior hydrogen delayed fracture resistance, method for manufacturing same, high strength bolt using same and method for manufacturing bolt

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1）

[0058] Steel materials having the composition of Table 1 and the temperature of Ae3 were manufactured, and then wire rods were manufactured using the steel materials under the conditions of Table 2. Bolts were made from the wire made above. In this case, the heat treatment conditions of the bolt manufacturing process are described in Table 2.

[0059] The tensile strength and hydrogen-induced delayed fracture resistance of each bolt manufactured as above were measured, and the results are shown in Table 3. The resistance to hydrogen-induced delayed fracture of each bolt was measured in such a way that the bolt had a tensile strength corresponding to about 0.9 times the tensile strength of each bolt, which was measured in the following state: each bolt was immersed in acid is about 2 and by H 2 O (2000cc), CH 3 COOH (80 ml) and NaCl (100 g) in a test solution, and then, the time (hours) after each sample was broken was measured. Through the test, it is estimated that the hy...

Embodiment 2）

[0070] In order to determine the hydrogen-induced delayed fracture resistance according to the size and aspect ratio of lanthanum (La)-based precipitates, nickel (Ni)-based precipitates, or LaNi-based precipitates, in the case of inventive examples 1 to 3, the precipitates were The size and aspect ratio of objects are changed by heat treatment.

[0071] After changing the size and aspect ratio of the precipitates as described above, the hydrogen-induced delayed fracture resistance was measured in the same manner as in the aforementioned Example 1, and the results are shown in Table 4.

[0072] Table 4

[0073]

[0074] As shown in Table 4, it can be confirmed that when the aspect ratio of the precipitate exceeds the range of the present invention, the hydrogen delayed fracture resistance is low.

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
tensile strengthaaaaaaaaaa
tensile strengthaaaaaaaaaa
tensile strengthaaaaaaaaaa
Login to View More

Abstract

The present invention relates to a wire rod used in bolts for automobile engines, for example, and more specifically to a wire rod having an improved resistance to hydrogen delayed fracture, to a manufacturing method for same, to a bolt using same and a method for manufacturing the bolt. Provided are a high strength wire rod having a superior resistance to hydrogen delayed fracture and a method for manufacturing same, a high strength bolt using the wire rod and a method for manufacturing same, wherein the wire rod comprises, 0.3-0.7 wt% C, 0.05-2.0 wt% Si, 0.7-1.5 wt% Mn, 0.01-0.1 wt% Ni, and 30-70 ppm La, and the remainder thereof is comprised by Fe and inevitable impurities.

Description

technical field [0001] The present invention relates to wire rods for automotive engine bolts and the like, and more particularly, to wire rods with improved hydrogen delayed fracture resistance, a method of manufacturing the same, high-strength bolts using the wire rods, and Method of making said bolt. Background technique [0002] In line with the current trend of weight reduction and high functionality of automobiles, there has been an increased demand for drive parts, especially engine parts (such as bolts, etc.), to have high strength in order to reduce energy consumption. The currently used high-strength bolts are made of alloy steel (such as SCM435, SCM440, etc.) through quenching and tempering processes, and have a tensile strength of 1200MPa. However, in bolts having a tensile strength of 1200 MPa or more, since delayed fracture can be easily caused by hydrogen, the application of using wire rods to manufacture ultra-high-strength bolts is still insufficient. [0...

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): C22C38/00C21D8/06
CPCC21D9/0093C22C38/12C22C38/005C21D9/525C21D8/065C22C38/04C22C38/08C22C38/02
Inventor 李侑焕金东炫柳根水
Owner POHANG IRON & STEEL CO LTD
Features
  • R&D
  • Intellectual Property
  • Life Sciences
  • Materials
  • Tech Scout
Why Patsnap Eureka
  • Unparalleled Data Quality
  • Higher Quality Content
  • 60% Fewer Hallucinations
Social media
Patsnap Eureka Blog
Learn More

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

© 2025 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap|About US| Contact US: help@patsnap.com