CN106319376B - A kind of novel low welding crack sensibility high-strength steel plate - Google Patents
A kind of novel low welding crack sensibility high-strength steel plate Download PDFInfo
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Abstract
The present invention discloses a kind of novel low welding crack sensibility high-strength steel plate, and the chemical composition in steel is by weight percentage：C：0.04%~0.06%, Si：0.10%~0.50%, Mn：1.10%~1.70%, P≤0.010%, S≤0.003%, Cr：0.35%~0.55%, Mo：0.05%~0.09%, Nb：0.04%~0.06%, V：0.02%~0.08%, remaining is Fe and inevitable impurity, Pcm=C+Si/30+ (Mn+Cu+Cr)/20+Ni/60+Mo/15+V/10+5B≤0.21.The steel plate is also equipped with good impact flexibility in the case of lower cost while can obtaining sufficient intensity.
Description
Technical field
The invention belongs to low-alloy steel field, more particularly to a kind of novel low welding crack sensibility high-strength steel plate.
Background technology
At present, domestic and international large-size spherical tank, power station penstock, spiral case are used with steel with low-welding crack-sensitive
Tensile strength 610MP ranks steel plate, general minimum temperature in use is -20 DEG C.Such steel plate collection high intensity, high tenacity and excellent
Different weldability is in one, using corresponding welding material welding, steel plate thickness reach 50mm also can not preheat or slightly heat and
Do not generate welding cold cracking.
Publication No. CN101096738A, CN101476080B, CN103160747A, CN103484766A,
In the patent of CN100516270C, CN102409251A, CN103031491A, CN102605293A, CN102758138B respectively
Describe to ensure that steel plate has -20 DEG C of certain low-temperature flexibilities, it is different degrees of be added to noble metal Ni (0.10%~
0.50%).For example, patent CN101476080B is added to 0.30%~0.50% Ni, patent CN102605293A in steel
0.10%~0.15% Ni is equally added in steel.In addition, in order to ensure the quenching degree of steel plate and anti-in above-mentioned patent
Tempering property is added to more than 0.10% Mo.For example, patent CN103160747A be added to 0.10% in steel~
0.30% Mo.Although ensure that the performance of steel plate in this way, the production cost of steel plate is also increased simultaneously.Equally, above-mentioned
In order to ensure steel plate Pcm (low-welding crack-sensitive index)≤0.21% in patent, it is reduced or avoided into steel and adds in Cr, and
Cr can not only improve the intensity of steel plate, the most important is the quenching degree that it can substitute Mo elements increase steel plate, obtain most
Good tempered sorbite or bainite tempered structure have a clear superiority in terms of Plate Production cost is reduced.For above-mentioned feelings
Condition, it would be highly desirable to be designed by novel components, develop a kind of low welding crack sensibility high-strength steel plate of low cost.
Invention content
The purpose of the present invention is to provide a kind of low welding crack sensitivity steel plates with low cost.
In order to achieve the above object, the present invention devises a kind of low welding crack sensitivity steel plate of low cost, feature
The chemical composition (% by weight) for being steel is：C：0.04%~0.06%, Si：0.10%~0.50%, Mn：1.10%~
1.70%th, P≤0.010%, S≤0.003%, Cr：0.35%~0.55%, Mo：0.05%~0.09%, Nb：0.04%~
0.06%th, V：0.02%~0.08%, remaining is Fe and inevitable impurity.Pcm=C+Si/30+ (Mn+Cu+Cr)/20+
Ni/60+Mo/15+V/10+5B (%)≤0.21%
The function analysis of above-mentioned chemical element is as follows：
C often forms carbide in steel with other alloying elements, can play invigoration effect to steel plate at room temperature, but higher
C be then unfavorable for the impact flexibility of steel plate, and also increase welding heat affected zone hardness and weld metal cold crack it is quick
The sensibility of perception and postwelding reheat cracking, therefore C content is limited to 0.04%~0.06%.
Si is present in as deoxidier in steel, it can increase the intensity of steel plate by solution strengthening in addition, but if Si contains
Amount is higher, then can lead to heat affected area deteriorated impact toughness, therefore Si contents are limited to 0.10%~0.50%.
Mn is as the main function element in phase transformation strengthening in steel and solution strengthening mechanism, other than improving armor plate strength,
Also have the function of to expand austenite phase field and reduce Ar3 point temperature.But too high levels are then being cast and are being generated in the operation of rolling
Segregation phenomena leads to the impact toughness decreased of steel plate, therefore Mn contents is limited to 1.10%~1.70%.
Mo can improve the quenching degree and anti-temper softening of steel plate, but add the excessive elongation percentage for not only seriously damaging steel plate
And sealing wire, while also causing the increase of Plate Production cost, it is contemplated that the Cr added in steel, which has, improves steel plate quenching degree
Situation only adds a small amount of Mo into steel to ensure its anti-temper softening, therefore Mo contents are limited to 0.05%~
0.09%.
Main adding elements of the Cr as this patent, effect are mainly reflected in two aspects, are on the one hand to reduce steel
In the case of middle Mo contents, ensure that steel plate has good quenching degree, so as to it is subsequent it is ultrafast it is cold during ensure that steel plate obtains
Martensite or bainite structure are obtained, tempered sorbite or bainite tempered structure are obtained by subsequent high tempering so that steel
Plate still has good low-temperature flexibility in the case where not adding Ni contents；On the other hand it is then to be made up by solution strengthening
Intensity caused by low-carbon is insufficient.Therefore Cr contents are limited to 0.35%~0.55%.
Main adding elements of the Nb as this patent, effect are not only in that crystal grain thinning and controlled rolling, more mainly
Be as carbonphile element, form a large amount of tiny carbonitride with the carbon in steel, by second-phase strength and refined crystalline strengthening come
Improve armor plate strength.Further, since it has grabbed a large amount of carbon in steel, avoid or reduce a large amount of Cr addition may caused by
The precipitation of strip carbide is grown up, and prevents the impact flexibility of damage steel plate, therefore Nb contents are limited to 0.04%~0.06%.
V can be precipitated by V (C, N) in lath of bainite, steel plate anti-temper softening be improved, so as to make up the drop of Mo contents
The decrease of steel plate anti-temper softening caused by low, the matching of realization armor plate strength, toughness do not damage the sealing wire of steel plate simultaneously,
Therefore V content is limited to 0.02%~0.08%.
The production method that the present invention uses is converter-offline tempering process of continuous casting-TMCP+, specially：
The casting technique of the present invention is recommended using continuous casting process, continuous casting process priority control cast temperature, Metal in Tundish
Cast temperature≤1540 DEG C, low temperature casting is preferable, to refine original as-cast structure.Continuous casting billet center Mn is segregated in order to control, is used
Electromagnetic agitation or continuous casting billet slighter compress technique, slighter compress amount are controlled between 3%~10%.
About heating temperature, it is necessary to select between 1050~1250 DEG C.When less than 1050 DEG C of heating, given birth in solidification
Into there is dysgenic coarse field trash to be possible to toughness with non-fusible state remain；And higher than 1250 DEG C heating, then have
It may make the precipitate re-melting generated in casting process by controlling cooling velocity.
The rolling mill practice of steel after the heating uses Direct Rolling and austenite perfect recrystallization area+austenite Unhydrated cement
Two stage control rolling mill practices.Steel plate of the present invention uses austenite perfect recrystallization area+rank of austenite Unhydrated cement two
Section controlled rolling technique.In perfect recrystallization temperature range, big rolling pass reduction ratio carries out quick continuous rolling, it is ensured that becomes
Dynamic/Static Recrystallization, fining austenite grains, thus rolling pass reduction ratio >=15%, maximum depression rate occur for shape metal
It is 25%；Recrystallization zone (1100~950 DEG C) total reduction >=55%；Controlled rolling is not being carried out in crystal region, it is brilliant to ensure
The effect of grain refinement should make rolling pass reduction ratio >=15%, not so as to achieve the purpose that the yield strength and toughness of raising steel
Recrystallization zone (910~850 DEG C) total reduction >=60%, largest cumulative deflection are 80%.
After hot-rolled steel plate, temperature is subjected to press quenching in the steel plate of more than Ar3, steel plate enter coolant-temperature gage for 750~
800 DEG C, the final cooling temperature of steel plate is controlled at 300 DEG C hereinafter, the cooling velocity of steel plate is controlled in 10~30 DEG C/s.Steel plate use from
Line tempering heat treatment, 600~690 DEG C of temperature.
Advantageous effect
The present invention is simple, reasonable in steel grades design, by element additive amount and type principle few as possible, rationally adjusts
The proportional quantity of whole each element, by adding Cr, Nb element, eliminating noble metal Ni in steel and reducing Mo contents so that steel plate exists
In the case of lower cost, still ensure that steel plate is also equipped with good impact flexibility while sufficient intensity is obtained.
Specific embodiment
The chemical composition of steel of the present invention is：C：0.04%~0.06%, Si：0.10%~0.50%, Mn：1.10%~
1.70%th, P≤0.010%, S≤0.003%, Cr：0.35%~0.55%, Mo：0.05%~0.09%, Nb：0.04%~
0.06%th, V：0.02%~0.08%, remaining is Fe and inevitable impurity, Pcm=C+Si/30+ (Mn+Cu+Cr)/20+
Ni/60+Mo/15+V/10+5B≤0.21.The production technology of the present embodiment is：Using Liquid Iron Pretreatment Technology, converter smelting, LF
The clean steels technique metallographics such as stove+VD (or RH) stove vacuum processing smelt production department's molten steel, and continuous casting billet is made by slab caster,
Continuous casting billet center Mn is segregated in order to control, and using continuous casting billet slighter compress technique, for the control of slighter compress amount 5%, the section of continuous casting billet is thick
It spends for 300mm.
The hot rolling of the present embodiment and cooling technique are：Continuous casting billet is heated to 1050~1250 DEG C, soaking 1.5~2.5 hours；
Its light plate is using two-stage controlled rolling process (recrystallization zone rolling+Unhydrated cement rolling), first stage rolling single pass pressure
Lower rate keeps 15%~25%, and second stage rolling cumulative deformation is maintained at 60%~80%；Rear steel plate is rolled to be quenched online
Fire, the coolant-temperature gage that enters of steel plate is 800 DEG C, the final cooling temperature of steel plate<300 DEG C, the cooling velocity of steel plate is in 20~25 DEG C/s.
The heat treatment process of the present embodiment is：Steel plate uses offline tempering heat treatment, 600~690 DEG C of temperature.
1 embodiment chemical component weight % of table
2 rolling mill practice system of table
Conventional mechanical property at 3 embodiment thickness 1/4 of table
It can be seen from above-described embodiment that the proportional quantity of the invention by rationally adjusting each element, addition Cr, Nb member
Element does not add Ni and reduces Mo contents, makes steel plate in the case of lower cost, is also equipped with while obtaining sufficient intensity good
Impact flexibility.
Claims (3)
- A kind of 1. low welding crack sensitivity steel plate with low cost, which is characterized in that the chemical composition by weight hundred in steel Ratio is divided to be calculated as：C：0.04%th, Si：0.13%th, Mn：1.14%th, P：0.007%th, S：0.002%th, Cr：0.36%th, Mo： 0.05%th, Nb：0.04%th, V：0.02%, remaining is Fe and inevitable impurity, Pcm=C+Si/30+ (Mn+Cu+Cr)/20 + Ni/60+Mo/15+V/10+5B is 0.13；The heating temperature of steel billet is 1050~1250 DEG C, and soaking 1.5~2.5 hours, rolling mill practice is tied again completely using austenite Crystalline region+stage control the rolling mill practice of austenite Unhydrated cement two, roughing start rolling temperature are 1097 DEG C, and roughing finishing temperature is 979 DEG C, single pass heavy deformation is 15.8%~24.3%, and finish rolling start rolling temperature is 910 DEG C, and finish rolling finishing temperature is 860 DEG C, is tired out Product deflection is 76.5%, and it is 800 DEG C to open cold temperature, 300 DEG C of final cooling temperature ＜；After hot rolling, quenched online in more than Ar3 Fire, it is 800 DEG C that steel plate, which enters coolant-temperature gage, and final cooling temperature is at 300 DEG C hereinafter, cooling velocity is 20~25 DEG C/s；Steel plate is using offline Tempering heat treatment, 600~690 DEG C of temperature；Finished steel plate thickness is 15mm, yield strength 555MPa, and tensile strength is 640MPa, elongation 26.5%, -20 DEG C of ballistic works are respectively 231J, 225J, 213J.
- A kind of 2. low welding crack sensitivity steel plate with low cost, which is characterized in that the chemical composition by weight hundred in steel Ratio is divided to be calculated as：C：0.05%th, Si：0.29%th, Mn：1.40%th, P：0.008%th, S：0.003%th, Cr：0.41%th, Mo： 0.07%th, Nb：0.05%th, V：0.05%, remaining is Fe and inevitable impurity, Pcm=C+Si/30+ (Mn+Cu+Cr)/20 + Ni/60+Mo/15+V/10+5B is 0.16；The heating temperature of steel billet is 1050~1250 DEG C, and soaking 1.5~2.5 hours, rolling mill practice is tied again completely using austenite Crystalline region+stage control the rolling mill practice of austenite Unhydrated cement two, roughing start rolling temperature are 1100 DEG C, and roughing finishing temperature is 983 DEG C, single pass heavy deformation is 15.6%~20.6%, and finish rolling start rolling temperature is 900 DEG C, and finish rolling finishing temperature is 854 DEG C, is tired out Product deflection is 62.8%, and it is 800 DEG C to open cold temperature, 300 DEG C of final cooling temperature ＜；After hot rolling, quenched online in more than Ar3 Fire, it is 800 DEG C that steel plate, which enters coolant-temperature gage, and final cooling temperature is at 300 DEG C hereinafter, cooling velocity is 20~25 DEG C/s；Steel plate is using offline Tempering heat treatment, 600~690 DEG C of temperature；Finished steel plate thickness is 30mm, yield strength 533MPa, and tensile strength is 630MPa, elongation 26.0%, -20 DEG C of ballistic works are respectively 244J, 250J, 248J.
- A kind of 3. low welding crack sensitivity steel plate with low cost, which is characterized in that the chemical composition by weight hundred in steel Ratio is divided to be calculated as：C：0.06%th, Si：0.48%th, Mn：1.70%th, P：0.007%th, S：0.002%th, Cr：0.53%th, Mo： 0.09%th, Nb：0.06%th, V：0.08%, remaining is Fe and inevitable impurity, Pcm=C+Si/30+ (Mn+Cu+Cr)/20 + Ni/60+Mo/15+V/10+5B is 0.20；The heating temperature of steel billet is 1050~1250 DEG C, and soaking 1.5~2.5 hours, rolling mill practice is tied again completely using austenite Crystalline region+stage control the rolling mill practice of austenite Unhydrated cement two, roughing start rolling temperature are 1123 DEG C, and roughing finishing temperature is 987 DEG C, single pass heavy deformation is 15.8%~23.6%, and finish rolling start rolling temperature is 890 DEG C, and finish rolling finishing temperature is 856 DEG C, is tired out Product deflection is 61.3%, and it is 800 DEG C to open cold temperature, 300 DEG C of final cooling temperature ＜；After hot rolling, quenched online in more than Ar3 Fire, it is 800 DEG C that steel plate, which enters coolant-temperature gage, and final cooling temperature is at 300 DEG C hereinafter, cooling velocity is 20~25 DEG C/s；Steel plate is using offline Tempering heat treatment, 600~690 DEG C of temperature；Finished steel plate thickness is 50mm, yield strength 515MPa, and tensile strength is 618MPa, elongation 25.3%, -20 DEG C of ballistic works are respectively 262J, 259J, 267J.
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| CN107937807B (en) * | 2017-11-18 | 2020-10-02 | 武汉钢铁有限公司 | 770 MPa-grade low-welding-crack-sensitivity pressure vessel steel and manufacturing method thereof |
| CN109628828B (en) * | 2018-12-27 | 2020-11-20 | 江阴兴澄特种钢铁有限公司 | Low-yield-ratio ultra-thick hydroelectric high-strength steel plate and manufacturing method thereof |
| CN110157985B (en) * | 2019-05-31 | 2021-09-21 | 张家港华程机车精密制管有限公司 | Steel plate for chord web arm of crawler crane and thermal hardening and tempering process performed on steel plate |
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| CN101418418A (en) * | 2007-10-26 | 2009-04-29 | 宝山钢铁股份有限公司 | Low welding crack sensitivity steel plate with yield strength of 690MPa grade and method for producing the same |
| CN102732797A (en) * | 2012-06-14 | 2012-10-17 | 莱芜钢铁集团有限公司 | 800MPa grade low welding crack sensitivity steel plate and its manufacturing method |
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| JPH03173715A (en) * | 1989-11-30 | 1991-07-29 | Kobe Steel Ltd | Production of 50kgf/mm2 class refractory steel for construction use excellent in weldability |
| JPH08333623A (en) * | 1995-06-07 | 1996-12-17 | Kobe Steel Ltd | Production of refractory steel material for building construction, excellent in earthquake resistance and reduced in yield ratio |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN101418418A (en) * | 2007-10-26 | 2009-04-29 | 宝山钢铁股份有限公司 | Low welding crack sensitivity steel plate with yield strength of 690MPa grade and method for producing the same |
| CN102732797A (en) * | 2012-06-14 | 2012-10-17 | 莱芜钢铁集团有限公司 | 800MPa grade low welding crack sensitivity steel plate and its manufacturing method |
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