CN100348742C

CN100348742C - Spheroidal annealing process of deep-punched steel plate for preventing bullet

Info

Publication number: CN100348742C
Application number: CNB2006100575362A
Authority: CN
Inventors: 董瀚; 时捷; 王琪
Original assignee: Central Iron and Steel Research Institute
Current assignee: Central Iron and Steel Research Institute
Priority date: 2006-03-14
Filing date: 2006-03-14
Publication date: 2007-11-14
Anticipated expiration: 2026-03-14
Also published as: CN1814822A

Abstract

The present invention belongs to the technical field of metal heat treatment, and is particularly to suitable for the spheroidizing annealing treatment technology of a deep-punching steel board used for a bulletproof helmet. The technology has the following concrete steps: step 1, heat preservation is carried out for 2 to 10 hours in the range of 10 to 50 DEG C below Ac 1, and the temperature of the heat preservation is from 650 to 690 DEG C; step 2, the heat preservation is carried out for 2 to 10 hours in the range from Ac 1 to Ac 3, and the temperature of the heat preservation is from 720 to 760 DEG C, and is a littler higher than that of Ac 1; step 3, the heat preservation is carried out for a long time of 10 to 30 hours at the temperature of 10 to 70 DEG C below Ac1, the temperature of the heat preservation is from 630 to 690 DEG C, and thus, the austenite structure is sufficiently converted into the carbide of ferrite and spheroidite. Compared with the prior art, the present invention has the advantages that the steel board after spheroidizing annealing has excellent plasticity and toughness, and the excellent mechanical processing performance is guaranteed so as to reduce the punching breakage rate of a helmet and the thinning rate of a head top part.

Description

A kind of spheroidal annealing process of deep-punched steel plate for preventing bullet

Technical field

The invention belongs to the metal heat treatmet technology field, be specially adapted to the spheroidal annealing process of deep-punched steel plate for preventing bullet.

Background technology

Usually, the shellproof steel helmet is to adopt armour plate after the Spheroidizing Annealing to carry out punching press to finish net shape.The degree at the breakage rate of punching course and helmet top attenuate of the helmet all is that the Spheroidizing Annealing degree by steel plate decides.Carbide annealing process is to eliminate because hot-work and the various stress and the harmful structure that produce with postcooling reduce hardness, improves plasticity, improves punching press lumber recovery and helmet top reduction simultaneously.

In the prior art, near the Ac1 line, be incubated for some time for common employing of deep drawing sheet steel traditional technology, change up and down at the Ac1 line by temperature, holding temperature about 715 ℃, soaking time 60 hours, annealing temperature height like this, make the carbide chap, easily form proeutectoid carbide in irregular shape in the steel and separate out comparatively small amt, and skewness along austenite grain boundary.Cause whole plasticity, the toughness of steel to decrease, thereby make the punching press breakage rate of the helmet increase and the reduction rising of crown portion, influenced the lumber recovery of product.

Summary of the invention

The object of the present invention is to provide a kind of spheroidal annealing process of deep-punched steel plate for preventing bullet, make bulletproof halmet have good plasticity and toughness by this technology with steel plate, guaranteed that machinability is good, thereby reduced helmet punching press breakage rate and crown portion reduction.

According to above-mentioned purpose, the present invention adopts following solution:

The concrete chemical ingredients (weight %) of deep-punched steel plate for preventing bullet is: C:0.38-0.45%, and Si0.1-1.8%, Mn 0.1-1.4%, P≤0.015%, S≤0.012%, Cr:0.8-1.5%, Ni0.8-2.0%, Mo:0.2-0.6%, surplus is Fe.

Carry out spheroidal annealing process at the deep-punched steel plate for preventing bullet that adopts above-mentioned chemical ingredients, the concrete steps of this technology are as follows:

(1) be incubated 2-10 hour in the following 10-50 of Ac1 ℃ scope, holding temperature is 650-690 ℃; Guarantee that original structure separates out carbide forming core tiny and that be evenly distributed, it is easy to the later stage nodularization;

(2) be incubated 2-10 hour in Ac1 and Ac3 scope, holding temperature is 720-760 ℃, a little higher than Ac1; This moment because of austenitic temperature near Ac1, the easy refinement of crystal grain, concentration is inhomogeneous again, easily forms a large amount of undissolved carbide as particle, thereby obtains the carbide of nodularization;

(3) the following 10-70 of Ac1 ℃ of long period insulation 10-30 hour, holding temperature was 630-690 ℃, makes austenite structure fully change the carbide of ferrite and nodularization into.

The effect of carbide annealing process fs and temperature range are selected according to as follows: be incubated 2-10 hour in the following 10-50 of Ac1 ℃ scope, holding temperature 650-690 ℃, impelling to have the proeutectoid carbide of more small and dispersed to separate out in the steel, and is evenly distributed;

The effect of carbide annealing process subordinate phase and temperature thereof are selected according to as follows: insulation is 2-10 hour in Ac1 and Ac3 scope, holding temperature is 720-760 ℃, and a little higher than Ac1 is incubated in high temperature section, finish the hypoeutectoid austenitic transformation, eliminate the defective that in former hot procedure, produces.Like this, guarantee the homogeneity of steel, for fully separating out of next step globular carbide made necessary preparation.

The effect of carbide annealing process phase III and temperature thereof are selected according to as follows: the following 10-70 of Ac1 ℃ of long period insulation 10-30 hour, holding temperature 630-690 ℃, make more proeutectoid carbide homogeneous nucleation.Its ceiling temperature should guarantee carbide energy homogeneous nucleation, so that can there be more spheroidized carbide to separate out in the steel, and is evenly distributed.

The present invention compared with prior art has good plasticity and toughness through the steel plate of Spheroidizing Annealing, has guaranteed that machinability is good, thereby has reduced the advantage of helmet punching press breakage rate and crown portion reduction.Specific as follows: Spheroidizing Annealing reduction in processing time or do not increase, the annealed structure and the mechanical property of steel have been improved, the carbide of separating out in the steel is fully fully separated out from austenite, and uniform distribution, improve the plasticity of steel effectively, obviously reduced helmet punching press breakage rate and crown portion reduction.Wherein, helmet punching press breakage rate is 1-3%, and crown portion reduction is 5-7%, unit elongation A ₅% 〉=28%.

Description of drawings

Accompanying drawing 1 adopts the metallographic structure stereoscan photograph (multiple 500 *) of prepared embodiment 1 deep drawing sheet steel of the present invention.

Accompanying drawing 2 adopts the metallographic structure stereoscan photograph (multiple 500 *) of the deep drawing sheet steel of prepared embodiment 2 of the present invention.

Accompanying drawing 3 adopts the metallographic structure stereoscan photograph (multiple 500 *) of the deep drawing sheet steel of prepared embodiment 3 of the present invention.

Accompanying drawing 4 adopts the traditional technology method to prepare the metallographic structure stereoscan photograph (multiple 500 *) of the deep drawing sheet steel of Comparative Examples 4.

Accompanying drawing 5 adopts traditional technology to prepare the metallographic structure stereoscan photograph (multiple 500 *) of the deep drawing sheet steel of Comparative Examples 5 with method.

Embodiment

At 3 batches of bulletproof halmets commonly used deep drawing sheet steel with thick 3.0mm, adopting technology of the present invention that above 3 batches of deep drawing sheet steels are carried out Spheroidizing Annealing handles, draw lot number and be 1,2, the embodiment of the invention of 3#, be that the deep drawing sheet steel of 2# utilizes traditional technology to draw that lot number is 4, the prior art Comparative Examples of 5# at chemical ingredients.The concrete chemical ingredients (weight %) of deep-punched steel plate for preventing bullet is listed in table 1, the concrete processing step and the processing parameter of technology of the present invention and traditional technology are listed in table 2, and 3 batches are adopted technology of the present invention and 2 batches to adopt the mechanical property comparing result of the deep-punched steel plate for preventing bullet for preparing after the traditional technology to list in table 3.

From Fig. 1-5 as can be seen the spherodized structure of novel process steel plate obviously improve, in the alloy structure after carbide annealing process of the present invention is handled, its proeutectoid carbide quantity is many, and disperse and being evenly distributed, in the alloy structure after traditional annealing process is handled, its proeutectoid carbide quantity obviously is less than the present invention.From table 2 and 3, can see the employing of novel process, the Spheroidizing Annealing treatment time is shortened or do not increase, and improved the spheroidal annealing quality of steel plate effectively, guaranteed that higher hardness has good plasticity and toughness simultaneously again, guaranteed that machinability is good, thereby obviously reduced the advantage of helmet punching press breakage rate and reduction.

The concrete chemical component table (wt%) of table 1 deep-punched steel plate for preventing bullet of the present invention

Steel grade	Lot number	C	Si	Mn	Cr	Ni	Mo	P	S	Fe
Steel grade	Lot number	C	Si	Mn	Cr	Ni	Mo	P	S	Fe	Deep-punched steel plate for preventing bullet of the present invention	1	0.39	0.25	0.23	1.00	1.30	0.20	0.010	0.008	Surplus
2	0.43	1.30	1.39	0.82	0.80	0.43	0.012	0.010	Surplus			1	0.39	0.25	0.23	1.00	1.30	0.20	0.010	0.008	Surplus
2	0.43	1.30	1.39	0.82	0.80	0.43	0.012	0.010	Surplus	3		0.45	1.78	0.23	1.20	2.00	0.54	0.009	0.007	Surplus

The concrete processing step of table 2 carbide annealing process of the present invention and traditional carbide annealing process and processing parameter contrast table

Table 3 adopts the deep-punched steel plate for preventing bullet mechanical property contrast table for preparing behind carbide annealing process of the present invention and the traditional carbide annealing process

Lot number		Rm MPa	Rp0.2 Mpa	A ₅ ％	Helmet punching press breakage rate %	The reduction % of crown portion	Metallographic structure	HB
Lot number		Rm MPa	Rp0.2 Mpa	A ₅ ％	Helmet punching press breakage rate %	The reduction % of crown portion	Metallographic structure	HB	The embodiment of the invention	1	575	440	31	1-2	5％	Fig. 1	172
2	590	460	29	2-3	7％	Fig. 2	175			1	575	440	31	1-2	5％	Fig. 1	172
2	590	460	29	2-3	7％	Fig. 2	175	3		600	475	28	2-3	6％	Fig. 3	179
Comparative Examples	4	655	510	23	25	30％	Fig. 4	3		600	475	28	2-3	6％	Fig. 3	179	197
	4	655	510	23	25	30％	Fig. 4	5	625	495	26	17	26％	Fig. 5	188		197

Claims

1, a kind of spheroidal annealing process of deep-punched steel plate for preventing bullet is characterized in that the concrete steps of this technology are as follows:

(1) at first be incubated 2-10 hour in the following 10-50 of Ac1 ℃ scope, holding temperature is 650-690 ℃;

(2) be incubated 2-10 hour then in Ac1 and Ac3 scope, holding temperature is 720-760 ℃, a little higher than Ac1;

(3) at last the following 10-70 of Ac1 ℃ of insulation 10-30 hour, holding temperature is 630-690 ℃, makes austenite structure fully change the carbide of ferrite and nodularization into.