JPS58120738A - Manufacture of pc steel wire and steel rod - Google Patents

Abstract

PURPOSE:To elevate relaxation, by straightening a steel material before or after heat treatment, by use of a wet type straight line machine, and reducing the relaxation without reducing uniform elongation of the steel material by a cooling function. CONSTITUTION:A straightening die 5 and a straight steel material to be straightened 1 are cooled by fitting each one piece of cooling rings 4, 4' to the inlet of a wet type straight line machine, and jetting a cooling liquid from a cooling liquid jet hole 9 of the cooling rings 4, 4', and also a lubricating film is formed between the straightening die 5 and the straight steel material 1 to be straightened. Accordingly, when the straight steel material 1 to be straightened is led into the wet type straight line machine and is straightened, a surface temperature of the straight steel material 1 to be straightened only rises to about 20 deg.C, moderate and uniform straightening is executed, and the relaxation is reduced without reducing the uniform elongation.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a 201141w steel bar (hereinafter referred to as "steel bar") having excellent luxation under high temperature and high pressure.

Traditionally, most of the curing methods for concrete piles, balls, etc. have been the normal temperature and normal pressure curing method (at 60°C - (capital)), but recently the high temperature and high pressure curing method (autoclave at 180°C to 200°C) has become popular. I came.

This is a major advantage in that the conventional room temperature and pressure curing method requires a day of curing after concrete pouring, whereas the high temperature and high pressure curing method allows curing to be completed in a short period of time and the product can be commercialized.

However, the phenomenon of relaxation increases as the temperature increases, and stress decreases.

In the case of steel bars, because they are used for the purpose of applying pressure line stress to concrete, relaxation stress is one of the important strength properties, and in high temperature and high pressure curing, the relaxation stress decreases. desired.

Therefore, various methods have been developed to reduce relaxation under high temperature and high pressure curing, but few have actually been put into practical use.

The reason for this is, for example, even with the heat stretching method, if a coiled object is continuously heat stretched, it must be straightened using a straightening machine before or after tempering or bluing to improve linearity. However, when straightening using a conventional dry straightening machine, there is a problem in that uniform elongation decreases before tempering or bluing, and elongation increases afterward.

Also, is there a way to improve relaxation by performing dry straightening on martensitic structures?This method produces results similar to heat stretching, so recently a warm straightening method has been developed. However, although this method improves relaxation, there are problems in that uniform elongation decreases and yield ratio becomes abnormally high.

In order to solve all of these problems, the method of the present invention has been developed through various experiments to straighten the steel *ttS with the wet straightener of the present invention. Even if it is adjusted beforehand, there is little decrease in uniform elongation, which is a problem in the past, and relaxation improves steadily.

In addition, there is no scratch on the surface caused by the straightening die, which was a problem in the past, and the wear of the straightening die is greatly reduced, making it possible to perform constant straightening for a long time.

The reason for this is that in the case of conventional dry straightening machines, the contact resistance between the straightening machine straightening die and the steel to be straightened is large, even if the surface temperature of the steel to be straightened before entering the straightening machine is room temperature (20℃). When it comes out of the straight machine, it has a diameter of 9.2cm and is about 140C.
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This is thought to be due to the poor slippage of the steel material passing through the straightening die, resulting in excessive straightening in some parts, which reduces uniform elongation.

The present invention aims to improve the shortcomings of the dry straightening machine, to have a cooling function, to completely reduce elongation of the steel material, and to improve relaxation by using a wet straightening machine to straighten desired steel wire and steel material. It is intended to be manufactured.

The present invention is a method for straightening steel materials using a TM type straightener before or after heat treatment such as quenching and tempering,
This is a method for producing a PO steel wire and rod, characterized by improving the relaxation properties of the steel material through its cooling function.

In the case of the wet straightening machine according to the method of the present invention, unlike the conventional dry straightening machine, 61 cooling rings 4.4' each are installed at the entrance and exit of the straightening machine as shown in OIWJK.
Coolant 11 (water or oil) is injected from the coolant injection hole 9 of the straightening die 5 of the I1 length straight machine and the steel to be straightened #1.
Table 2 Mechanical properties by dry straight machine straightening method (straightening before tempering) 7 / Table 3 Mechanical properties by dry straight machine warm straightening method (straightening after tempering)

[Brief explanation of drawings]

Figure 21 is a sectional view of the wet linear machine of the present invention, Figure 2 is a sectional view of the cooling ring, and Figure 3 is a front view of the same. ; l is the steel material to be straightened, 2.2' is the bearing, 3.3' is the coolant inlet, 4.4' is the cooling ring, 5 is the straightening die, 6#'i
Coolant outlet, 7 is power m (pulley), 8 is cooling ring body, 9Fi coolant injection hole, 10 is ignition. Procedural amendment (spontaneous) February 13, 1920 Revised Japan Patent Office Commissioner Shima 1) Haruki Tono1, Indication of case Patent Nos. 1857-22902, Title of invention Method for manufacturing PO steel wire and steel bar3, Make amendments Relationship to the incident: Applicant: Hokkai Koki Co., Ltd. 5, subject of amendment: Wi4JI! The contents of the document include the scope of claims, detailed descriptions of the invention, and the main page. 6. Contents of amendments (1) Amendments to gA specifications are attached. rtl It and Figure 3 in the drawings have been corrected as indicated in the appendix. Amendment O Contents Application number Patent @ 57-2290 The 11 specifications of this application are amended as follows. 1. Patent claim 0111 in the specification! Correct the zero pressure below the pipe. ``Claims: Straighten the steel material before or after heat treatment using a wet straightening machine and use a cooling function to reduce straightness without reducing uniform elongation.'' 2. Method for manufacturing RA steel wire and steel rod. i1 Specification Page 3, Line 1, Page 3, Line 5, 3
The word "improvement" in the buy-off line and the 4th off-line has been corrected to "decrease." 3. Specification No. 3] In line 5, the phrase ``uniform elongation has decreased'' has been amended to ``uniform elongation has also decreased.'' 4. On page 4 of the specification, on line 6, next to "Decrease" □ Add "without". 5. On page 4 of the specification, line 8, “Steel materials” should be replaced with “Steel bars.”
and correct it. 6, page 4, lines 10 to 14 of the v4 specifications, ``The present invention is an 11-1 manufacturing method.'' is deleted. There were some omissions and typos in the γ g stomach code, so the 1 year old 1 figure and the 3 year old figure were corrected in the attached sheet-mo:ab. Showa Shoulder February 13th Applicant: Hokkai Koki Co., Ltd. Kinsha

Claims (1)

[Claims] Improving the relaxation of steel materials by straightening and setting cooling functions using a straightening machine for steel pipe types before or after heat treatment.
A method for manufacturing an A0 steel wire and steel bar having taclI and tIII# characteristics.