CN103555912B - A kind of 30Cr3MoV steel that utilizes is for the method for raw material production plug - Google Patents

Abstract

The invention belongs to plug production technical field, be specifically related to a kind of 30Cr3MoV steel that utilizes for the method for raw material production plug, a kind of 30Cr3MoV steel that utilizes is for the method for raw material production plug, through selecting materials-refining-electroslag-forging-roughing-thermal treatment-precision work forms, the present invention selects 30Cr3MoV steel as raw material, adopts the refining of EAF+LF/VD mode, for improving purity, make crystal structure finer and close, thus obtain more high impact toughness.

Description

A kind of 30Cr3MoV steel that utilizes is for the method for raw material production plug

Technical field

The invention belongs to plug production technical field, be specifically related to a kind of 30Cr3MoV steel that utilizes for the method for raw material production plug.

Background technology

Plug is that modern technologies produce the necessary most important tool and mould of hot rolled seamless steel tube, its consuming cost accounts for 50% of milling train maintenance cost, this product environment for use in roll seamless steel tube process is severe, use temperature about 1150 DEG C, surface temperature can reach 600 ~ 800 DEG C within a short period of time, and with after at chill station water-spraying control, and again reach the standard grade rapidly and recycle.Bear repeatedly cold and heat succeed each other circulation and stronger thermal wear in the operation of rolling, also will bear the repeated load of complexity comparatively greatly, mainly scrapping defect is the crackle that the scuffing on check surface, wearing and tearing, ring crack and axis causes simultaneously.Along with going deep into plug product research, in conjunction with the service condition of each hot seamless tube factory, both sides of supply and demand also reach unanimity on the understanding affecting plug factor in work-ing life, namely by improving the breakdown point of material and impelling strength improves work-ing life, its core technology is the smelting of ultra-clean steel, forging and thermal treatment process.Now the most frequently used both at home and abroad a kind of mandrel material is H13(4Cr5MoSiV1) steel, its production cost is too high, and transverse impact toughness not easily ensures.For reaching low cost, high life object, the present invention adopts 30Cr3MoV to substitute H13(4Cr5MoSiV1) as mandrel material.

Summary of the invention

The object of the invention is to overcome deficiency of the prior art and provide a kind of 30Cr3MoV steel that utilizes for the method for raw material production plug, present method can while ensureing that material has the high strength limit, improve the impelling strength of plug to greatest extent, improve the work-ing life of plug, and effectively reduce production cost.

The object of the present invention is achieved like this:

A kind of 30Cr3MoV steel that utilizes is for the method for raw material production plug, through selecting materials-refining-electroslag-forging-roughing-thermal treatment-precision work forms, controlling Heating temperature before described forging is 1210-1230 DEG C, final forging temperature is 850 DEG C, oil press is adopted to carry out jumping-up during forging, control draught 20 ~ 24%, feed is 0.7 ~ 0.85 times of blank height; Normalizing+hardening and tempering process mode is adopted to carry out during described thermal treatment, normalizing temperature 930-970 DEG C, soaking time is 0.8 ~ 1h/100mm, and normalizing mist is chilled to room temperature, cooling rate 2 ~ 5 DEG C/min, then quench, quenching temperature is 900 ~ 940 DEG C, and soaking time is 0.8 ~ 1h/100mm, put into temperature after quenching to cool lower than the water base fluid of 25 DEG C, then carry out tempering at 590 ~ 660 DEG C, soaking time is 1.5 ~ 2h/100mm, below the air cooling to 100 DEG C of coming out of the stove.

Select 30Cr3MoV steel as raw material during described refining, adopt the refining of EAF+LF/VD mode, pour into electrode billet, electrode billet demoulding after heat power transmission slag, forging is sent in electroslag after heat.

Described refining process control electrode base chemical composition is: C=0.28 ~ 0.33%, Si=0.55 ~ 0.70%, Mn=0.40 ~ 0.60%, Cr=3.00 ~ 3.30%, Mo=0.45 ~ 0.55%, V=0.20 ~ 0.30%, S≤0.008%, P≤0.012%; Described Electroslag Process controls ESR ingot chemical composition: C=0.28 ~ 0.33%, Si=0.45 ~ 0.65%, Mn=0.40 ~ 0.60%, Cr=3.00 ~ 3.30%, Mo=0.45 ~ 0.55%, V=0.20 ~ 0.30%, S≤0.008%, P≤0.012%.

The present invention selects 30Cr3MoV steel as raw material, adopts the refining of EAF+LF/VD mode, for improving purity, make crystal structure finer and close, thus obtain more high impact toughness, after refining, pour into electrode billet, esr is sent in electrode billet demoulding after heat, and forging is sent in electroslag after heat; In forging process, need the strict draught and the feed that control oil press during jumping-up, effectively improve the lateral performance of workpiece, effectively steel ingot subsurface defect is closed in forging; Thermal treatment process adopts normalizing+modified mode to carry out, can crystal grain thinning and uniform formation and composition by normalizing, ready for quenching; After normalizing, mist is cold, speed of cooling is fast, crystal grain can refinement well, evenly microstructure and composition, adopt water base fluid cooling during quenching simultaneously, improve speed of cooling and full hardening deepness, make austenite structure fully be transformed into martensitic stucture, obtained the tempered sorbite of fine uniform again by high tempering, thus obtain higher comprehensive mechanical property.

Accompanying drawing explanation

Fig. 1 is thermal treatment process schema of the present invention.

Embodiment

Embodiment 1:

Plug steel grade is selected to be 30Cr3MoV, through selecting materials-refining-electroslag-forging-roughing-thermal treatment-precision work-chromium plating forms, EAF+LF/VD refining route is adopted after selecting materials, furnace charge is by secondary or the above steel scrap of secondary, return stub bar, the compositions such as sponge iron, tapping after EAF oxidation, pre-deoxidation and partially-alloyed in bag, carry out LF/VD ar blowing refining, weak stirring before tapping, churning time >=15min, argon for protecting pouring is adopted after tapping calmness, esr is sent in electrode billet demoulding after heat, ESR ingot surface is without being greater than 3mm slag runner, forging is sent in demoulding after heat, heat send temperature to be not less than 500 DEG C, refining process control electrode base chemical composition is: C=0.28 ~ 0.33%, Si=0.55 ~ 0.70%, Mn=0.40 ~ 0.60%, Cr=3.00 ~ 3.30%, Mo=0.45 ~ 0.55%, V=0.20 ~ 0.30%, S≤0.008%, P≤0.012%, Electroslag Process controls ESR ingot chemical composition: C=0.28 ~ 0.33%, Si=0.45 ~ 0.65%, Mn=0.40 ~ 0.60%, Cr=3.00 ~ 3.30%, Mo=0.45 ~ 0.55%, V=0.20 ~ 0.30%, S≤0.008%, P≤0.012%, then heat in formula gas furnace at the bottom of car, furnace temp is 1220 DEG C, blank temperature allows lower than furnace temperature 40 DEG C, final forging temperature is 850 DEG C, in forging process: adopt oil press jumping-up, control draught 20%, feed is 0.85 times of blank height, adopt 1800 tons of precise forging machine forgings, controlling distortion amount is 65mm, heat-treat after roughing, normalizing+hardening and tempering process mode is adopted to carry out, as shown in Figure 1, first carry out normalizing, normalizing temperature 940 DEG C, soaking time is 0.9h/100mm, axial blower is adopted after normalizing, water pipe is connected in fan blade, spraying is carried out pressure and is cooled to room temperature, for increasing mist air cooling effect, formula chassis both sides and front side at the bottom of car is placed in respectively with 8 Fans, be directly injected to workpiece from multiple orientation, workpiece is forced evenly to cool fast, in order to crystal grain thinning and uniform formation and composition, ready for quenching, modifier treatment technique is adopted after normalizing, quenching temperature is 920 DEG C, soaking time is 1h/100mm, workpiece heart portion is made to reach specified temperature, complete austenitic transformation and make its homogenizing, then the water base fluid continuous coo1ing being less than 25 DEG C is put into, obtain martensitic stucture, high tempering is carried out again at 620 DEG C, soaking time adopts 2 hours/100mm, the continuation carrying out martensite decomposition and residual austenite changes, obtain the tempered sorbite tissue of fine uniform, come out of the stove below air cooling to 100 DEG C, mechanical property meets the high strength limit of use and the requirement of impelling strength, then precision work and chromium plating is carried out.

Embodiment 2:

Plug steel grade is selected to be 30Cr3MoV, through selecting materials-refining-electroslag-forging-roughing-thermal treatment-precision work-chromium plating forms, EAF+LF/VD refining route is adopted after selecting materials, furnace charge is by secondary or the above steel scrap of secondary, return stub bar, the compositions such as sponge iron, tapping after EAF oxidation, pre-deoxidation and partially-alloyed in bag, carry out LF/VD ar blowing refining, weak stirring before tapping, churning time >=12min, argon for protecting pouring is adopted after tapping calmness, esr is sent in electrode billet demoulding after heat, ESR ingot surface is without being greater than 3mm slag runner, forging is sent in demoulding after heat, heat send temperature to be not less than 500 DEG C, refining process control electrode base chemical composition is: C=0.28 ~ 0.33%, Si=0.55 ~ 0.70%, Mn=0.40 ~ 0.60%, Cr=3.00 ~ 3.30%, Mo=0.45 ~ 0.55%, V=0.20 ~ 0.30%, S≤0.008%, P≤0.012%, Electroslag Process controls ESR ingot chemical composition: C=0.28 ~ 0.33%, Si=0.45 ~ 0.65%, Mn=0.40 ~ 0.60%, Cr=3.00 ~ 3.30%, Mo=0.45 ~ 0.55%, V=0.20 ~ 0.30%, S≤0.008%, P≤0.012%, then heat in formula gas furnace at the bottom of car, furnace temp is 1210 DEG C, blank temperature allows lower than furnace temperature 40 DEG C, final forging temperature is 850 DEG C, in forging process: adopt oil press jumping-up, control draught 24%, feed is 0.7 times of blank height, adopt 1800 tons of precise forging machine forgings, controlling distortion amount is 75mm, heat-treat after roughing, normalizing+hardening and tempering process mode is adopted to carry out, as shown in Figure 1, first carry out normalizing, normalizing temperature 930 DEG C, soaking time is 0.9h/100mm, axial blower is adopted after normalizing, water pipe is connected in fan blade, spraying is carried out pressure and is cooled to room temperature, for increasing mist air cooling effect, formula chassis both sides and front side at the bottom of car is placed in respectively with 8 Fans, be directly injected to workpiece from multiple orientation, workpiece is forced evenly to cool fast, in order to crystal grain thinning and uniform formation and composition, ready for quenching, modifier treatment technique is adopted after normalizing, quenching temperature is 910 DEG C, soaking time is 1h/100mm, workpiece heart portion is made to reach specified temperature, complete austenitic transformation and make its homogenizing, then the water base fluid continuous coo1ing being less than 25 DEG C is put into, obtain martensitic stucture, high tempering is carried out again at 600 DEG C, soaking time adopts 2 hours/100mm, the continuation carrying out martensite decomposition and residual austenite changes, obtain the tempered sorbite tissue of fine uniform, come out of the stove below air cooling to 100 DEG C, mechanical property meets the high strength limit of use and the requirement of impelling strength, then precision work and chromium plating is carried out.

Above two embodiments and corresponding reference examples product are tested by the existing testing standard of GB/T228 and GB/T229, result is as following table 1.The product that reference examples adopts common process to produce, air cooling after normalizing, speed of cooling is slow, and crystal grain is comparatively thick, and adopts oil quenching, and quench cooled earthquake intensity is weak, and it is on the low side to impact merit; And the product that present invention process is produced, after normalizing, mist is cold, speed of cooling is fast, crystal grain can refinement well, evenly microstructure and composition, adopts water base fluid cooling simultaneously, improves speed of cooling and full hardening deepness during quenching, make austenite structure fully be transformed into martensitic stucture, thus obtain higher comprehensive mechanical property.

The test data of table 1 embodiment 1-2 and reference examples product

Remarks: during impact absorbing energy test, a test piece has been got three lateral impact samples, corresponding three impact values.

Found out by upper table 1 data, the product comprehensive mechanical property that present invention process is produced is higher, and comprehensive mechanical property is obviously better than reference examples product, absolutely proves the significant superiority of the present invention.

Claims (1)

1. one kind utilizes 30Cr3MoV steel for the method for raw material production plug, through selecting materials-refining-electroslag-forging-roughing-thermal treatment-precision work forms, it is characterized in that: controlling Heating temperature before described forging is 1210-1230 DEG C, final forging temperature is 850 DEG C, oil press is adopted to carry out jumping-up during forging, control draught 20 ~ 24%, feed is 0.7 ~ 0.85 times of blank height; Normalizing+hardening and tempering process mode is adopted to carry out during described thermal treatment, normalizing temperature 930-970 DEG C, soaking time is 0.8 ~ 1h/100mm, and normalizing mist is chilled to room temperature, cooling rate 2 ~ 5 DEG C/min, then quench, quenching temperature is 900 ~ 940 DEG C, and soaking time is 0.8 ~ 1h/100mm, put into temperature after quenching to cool lower than the water base fluid of 25 DEG C, then carry out tempering at 590 ~ 660 DEG C, soaking time is 1.5 ~ 2h/100mm, below the air cooling to 100 DEG C of coming out of the stove;

Select 30Cr3MoV steel as raw material during described refining, adopt the refining of EAF+LF/VD mode, pour into electrode billet, electrode billet demoulding after heat power transmission slag, forging is sent in electroslag after heat;

Described refining process control electrode base chemical composition is: C=0.28 ~ 0.33%, Si=0.55 ~ 0.70%, Mn=0.40 ~ 0.60%, Cr=3.00 ~ 3.30%, Mo=0.45 ~ 0.55%, V=0.20 ~ 0.30%, S≤0.008%, P≤0.012%; Described Electroslag Process controls ESR ingot chemical composition: C=0.28 ~ 0.33%, Si=0.45 ~ 0.65%, Mn=0.40 ~ 0.60%, Cr=3.00 ~ 3.30%, Mo=0.45 ~ 0.55%, V=0.20 ~ 0.30%, S≤0.008%, P≤0.012%.