Quenching machine accelerated cooling method for improving strength of normalized steel plate with thickness specification of being greater than or equal to 50 mm

A technology of accelerated cooling and quenching machine, used in heat treatment equipment, furnaces, heat treatment process control and other directions, can solve the problem of low strength of steel plates, and achieve the effect of large strength improvement, increased strength, and increased nucleation rate

Inactive Publication Date: 2015-12-16
SHANDONG IRON & STEEL CO LTD
View PDF6 Cites 9 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The object of the present invention is to provide a quenching machine accelerated cooling method for improving the strength of the normalized steel plate with a thickness ≥ 50 mm, which solves the problem of low strength of the steel plate after normalizing, and the steel plate is under the condition of multiple batches of l

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
  • Quenching machine accelerated cooling method for improving strength of normalized steel plate with thickness specification of being greater than or equal to 50 mm

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] Aiming at the problem of insufficient strength margin of the normalized steel plate of the 50mm specification SM570N forklift beam, four low-pressure sections are turned on for water cooling. The opening of the 20-zone flow regulating valve is 53% / 78%, and the ratio of the upper and lower openings (water ratio) is 0.80-0.81; the roller speed is 23m / min; the average cooling speed is 8.9°C / S; The temperature is 612°C.

[0025] Under the condition of keeping the same composition, rolling and normalizing process, the average value of yield strength after conventional normalizing is 451MPa, and the average value of tensile strength is 592MPa, while the average value of yield strength after adopting normalizing and controlled cooling of the present invention is 533MPa, and the average value of tensile strength is 533MPa, and the average value of tensile strength is 688MPa, the overall strength is increased by 80-100MPa, and the performance margin of other indicators is reason...

Embodiment 2

[0027] In view of the insufficient strength margin of the 60mm specification S355NLZ35 marine engineering normalized steel plate, four low-pressure sections are turned on for water cooling. The opening of the flow regulating valve in the 20 zones is 56% / 79%, and the ratio of the upper and lower openings (water ratio) is 1.191; the roller speed is 20m / min; the average cooling speed is 9.3°C / S; the average temperature of the final cooling "returning red" is 608 ℃.

[0028] Under the condition of keeping the same composition, rolling and normalizing process, the average value of yield strength after conventional normalizing is 345MPa, and the average value of tensile strength is 502MPa, while the average value of yield strength after normalizing and controlled cooling of the present invention is 429MPa, the average value of tensile strength is 429MPa, and the average value of tensile strength is 595MPa, the overall strength is increased by 80-100MPa, and the performance margin of...

Embodiment 3

[0030] For the 80mm specification S460MZ25 structural steel plate shape incompatibility, six low-pressure sections are opened for water cooling, and the water cooling adjustment is as follows: the opening of the flow regulating valve in the 15th / 17th / 19th area of ​​the low-pressure section is 32% / 42% / 62%, respectively, and the 16th area The opening degree of the flow regulating valve in zone 18 / zone 20 is 37% / 49% / 72%, and the ratio of the upper and lower openings (water ratio) is 1.167; the roller speed is 18m / min; the average cooling rate is 9.5℃ / S; the final cooling The average temperature of "returning red" is 602°C.

[0031] Under the condition of keeping the same composition and rolling process, the average value of yield strength in TMCP state is 478MPa, and the average value of tensile strength is 615MPa, while the average value of yield strength after adopting normalizing and controlled cooling of the present invention is 482MPa, the average value of tensile strength is...

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
Yield strengthaaaaaaaaaa
Tensile strengthaaaaaaaaaa
Yield strengthaaaaaaaaaa
Login to view more

Abstract

The invention discloses a quenching machine accelerated cooling method for improving the strength of a normalized steel plate with the thickness specification of being greater than or equal to 50 mm. The quenching machine accelerated cooling method comprises the following steps: the normalized steel plate enters a quenching machine along a quenching machine roller way after being discharged from a quenching furnace to be subjected to water cooling, four or six low-pressure sections are confirmed to be opened according to steel varieties and specifications, and the opening degrees, the upper and lower opening degree ratios and the roller way speeds of the areas of the low-pressure sections are adjusted, so that the steel plate is naturally cooled after the 'self-tempering' temperature reaches 580-630 DEG C, wherein the water yield control parameters are as follows: the opening degree of a flow control valve at the 15 area of the low-pressure sections is 30-40%, and the opening degree of a flow control valve at the 16 area of the low-pressure sections is 35-50%; the opening degree of a flow control valve at the 17 area of the low-pressure sections is 40-50%, and the opening degree of a flow control valve at the 18 area of the low-pressure sections is 45-60%; the opening degree of a flow control valve at the 19 area of the low-pressure sections is 60-70%, and the opening degree of a flow control valve at the 20 area of the low-pressure sections is 65-80%; the steel plate cooling speed is controlled to be 8-10 DEG C/S. The water cooling uniformity is good, the plate form after the cooling is good, and the strength of the normalized steel plate can be greatly improved through water cooling.

Description

technical field [0001] The invention belongs to the technical field of normalizing and cooling control for wide and thick plates, and in particular provides an accelerated cooling method for a quenching machine for increasing the strength of normalizing steel plates with a thickness ≥ 50 mm. Background technique [0002] Low-alloy high-strength steel plates generally refer to structural steel plates with a yield strength of 460MPa and below. Steel plates with specifications ≥ 50 mm are usually delivered in a normalized state. After normalizing, the steel plate has little strength margin, especially the yield strength. It is close to or lower than the lower limit of the standard; in addition, for steel plates with specifications ≥50mm that are produced by controlled rolling (controlled cooling) technology, if the plate shape does not conform, it is difficult to save the plate shape through the straightening process, and the normalizing process is usually used to save it. The ...

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): C21D1/18C21D11/00C21D9/00
Inventor 高立福张长宏罗君高王月香陈爱娇吴德发李艳张鹏冯文义高海军
Owner SHANDONG IRON & STEEL CO LTD
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