CN102321847A - Quenching and tempering structure thick steel plate for offshore platform and production method for quenching and tempering structure thick steel plate - Google Patents

Abstract

The invention discloses a quenching and tempering structure thick steel plate with the yield strength of 420MPa for an offshore platform, and a production method for the quenching and tempering structure thick steel plate. The steel plate comprises the following chemical compositions in percentage by mass: 0.10 to 0.15 percent of C, 0.10 to 0.50 percent of Si, 1.0 to 1.6 percent of Mn, less than 0.015 percent of P, less than 0.005 percent of S, 0.015 to 0.050 percent of Als, 0.010 to 0.050 percent of Nb, 0.020 to 0.070 percent of V, 0.005 to 0.020 percent of Ti, 0.10 to 0.30 percent of Cr and the balance of Fe and inevitable impurities. The production method comprises the following steps of: heating a blank to the temperature of between 1,190 and 1,210DEG C, executing a rolling process, and performing air cooling after rolling; quenching at the temperature of between 890 and 930DEG C; and tempering at the temperature of between 600 and 650DEG C. The process is simple; and the quenching and tempering structure thick steel plate has high toughness, good processing and welding properties, low cost, and wide market prospect, and is high-quality superhigh-strength steel for ship structures.

Description

A kind of ocean platform is with modified structure Plate Steel and working method thereof

Technical field

The invention belongs to the HSLA production field, the ys 420MPa ocean platform that specifically a kind of hardening and tempering process is produced is with modified structure Plate Steel and working method thereof.

Background technology

Development along with marine resources development; Common 320MPa, 360MPa level ocean platform can not be satisfied the demand with steel; And along with weight, structure and the volume of the large ocean oil steelwork depth of water along with marine petroleum development continues to increase; Ocean structure constantly increases the weight of, and the steel plate thickness of works volume and use also continues to increase.And along with the requirement of the rising of price of steel product and ocean structure, marine erectility, the application of plow-steel is also adopted in big area, so just can reduce steel using amount.Mostly the material that small-sized ocean structure adopts is 355MPa even the lower material of intensity rank, and the employing ratio of large ocean platform structure 420MPa steel constantly increases.

Therefore be badly in need of developing energetically the above ocean platform of ys 420MPa and use structural steel and iron.

Summary of the invention

The ocean platform that the object of the present invention is to provide a kind of ys 420MPa is with modified structure Plate Steel and working method thereof; This steel plate adopts Nb, V, Ti, Cr microalloy composition, through smelting, rolling and thermal treatment process, the steel plate good combination property of production; Have high-strong toughness ability, well processed and welding property; And with low cost, market outlook are wide, are a kind of high-quality superstrength ship hull structure use steel.

The objective of the invention is to realize through following technical scheme:

A kind of ocean platform is characterized in that with modified structure Plate Steel: this steel plate chemical ingredients mass percent is: C: 0.10-0.15%, Si:0.10-0.50%; Mn: 1.0-1.6%, < 0.015%, S < 0.005% for P; Als:0.015-0.050%, Nb:0.010-0.050%, V:0.020-0.070%; Ti:0.005-0.020%, Cr:0.10-0.30%, surplus is Fe and inevitable impurity.

This steel plate chemical ingredients mass percent is preferably: C:0.13-0.15%, Si:0.25-0.35%, Mn:1.40-1.50%; P 0.015%, S 0.005%, Als:0.020-0.040%; Nb+V+Ti=0.070%, Cr:0.10-0.15%, all the other are Fe and inevitable impurity.

The performance index of steel plate of the present invention are: ys >=420MPa, tensile strength >=530-680MPa, elongation >=18.0%, impact of collision merit (40 ℃) >=42J.

A kind of ocean platform is characterized in that with the working method of modified structure Plate Steel: this working method comprises following process step: smelting, blank heating, rolling, air cooling, quench treatment and temper, and concrete process step is following:

1) become 150-320mm to satisfy the heavy slab that chemical ingredients requires molten steel casting; Roll the luggage stove heating of advancing, the process furnace tapping temperature is 1190-1210 ℃, heat-up time 10-13min/cm * slab thickness cm; This heavy slab chemical ingredients mass percent is: C: 0.10-0.15%, Si:0.10-0.50%, Mn: 1.0-1.6%; P 0.015%, S 0.005%, Als:0.015-0.050%; Nb:0.010-0.050%, V:0.020-0.070%, Ti:0.005-0.020%; Cr:0.10-0.30%, surplus is Fe and inevitable impurity;

2) in the roughing operation, start rolling temperature is 1100-1150 ℃, roughing finishing temperature >=1030 ℃; Intermediate blank treats that temperature thickness is finished product thickness 1.5-4.0 times;

3) finish rolling start rolling temperature≤950 ℃, finish rolling finishing temperature≤880 ℃;

4) air cooling after the finish rolling;

5) reheat quenching temperature: 890-930 ℃, tempering temperature 600-650 ℃, soaking time 1.0-2.0H wherein H is a steel plate thickness.

The steel sheet product that the present invention produces possesses good comprehensive performances: cold-bending property is good; Have high-strong toughness ability, well processed and welding property; And with low cost, market outlook are wide, and the ocean platform that is a kind of high-quality ys 420MPa is with modified structure Plate Steel.

 

Embodiment

A kind of ys 420MPa ocean platform of the present invention is with modified structure Plate Steel, and the composition of design is by weight percentage: C:0.14%, Si:0.25%; Mn:1.45%, P:0.010%, S:0.002%; Als:0.030%; Nb+V+Ti=0.070%, Cr:0.14%, all the other are Fe and inevitable impurity.Wherein: Nb:0.030%, V:0.030%, Ti:-0.010%.

Under the plate mill working condition, adopt sheet billet continuous casting, controlled rolling, air cooling and modified treatment production technology, concrete technological measure is following:

The production process aspect comprises smelting, blank heating, rolling, air cooling, quench treatment and temper.

Smelt and be cast into the 260mm heavy slab by above composition; Slab is sent into process furnace, 1205 ℃ of process furnace tapping temperatures, heat-up time 260min; The roughing start rolling temperature is 1150 ℃, 1036 ℃ of roughing finishing temperatures; Intermediate blank is treated temperature thickness 90mm; 860 ℃ of finish rolling start rolling temperatures, 860 ℃ of finish rolling finishing temperatures; Air cooling after the finish rolling; Quenching temperature: 910 ℃, 635 ℃ of tempering temperatures, soaking time 60 minutes; Product thickness 60mm.

The present invention adopts sheet billet continuous casting, controlled rolling, air cooling and modified treatment production technology under the plate mill working condition, successful production ys 420MPa ocean platform with modified structure Plate Steel.The R of product _EL=490N/mm ², R _m=590 N/mm ², elongation after fracture A=24% ,-40 ℃ of summers, cold-bending property was good than the vertical value=171J of impact absorbing energy, was a kind of high-quality superstrength ship hull structure use steel.

Claims (3)

1. an ocean platform is characterized in that with modified structure Plate Steel: this steel plate chemical ingredients mass percent is: C: 0.10-0.15%, Si:0.10-0.50%; Mn: 1.0-1.6%, < 0.015%, S < 0.005% for P; Als:0.015-0.050%, Nb:0.010-0.050%, V:0.020-0.070%; Ti:0.005-0.020%, Cr:0.10-0.30%, surplus is Fe and inevitable impurity.

2. ocean platform according to claim 1 is characterized in that with modified structure Plate Steel: this steel plate chemical ingredients mass percent is: C:0.13-0.15%, Si:0.25-0.35%; Mn:1.40-1.50%, < 0.015%, S < 0.005% for P; Als:0.020-0.040%; Nb+V+Ti=0.070%, Cr:0.10-0.15%, all the other are Fe and inevitable impurity.

3. an ocean platform is with the working method of modified structure Plate Steel, and it is characterized in that: this working method comprises following process step: smelting, blank heating, rolling, air cooling, quench treatment and temper, and concrete process step is following:

1) become 150-320mm to satisfy the heavy slab that chemical ingredients requires molten steel casting; Roll the luggage stove heating of advancing, the process furnace tapping temperature is 1190-1210 ℃, heat-up time 10-13min/cm * slab thickness cm; This heavy slab chemical ingredients mass percent is: C: 0.10-0.15%, Si:0.10-0.50%, Mn: 1.0-1.6%; P 0.015%, S 0.005%, Als:0.015-0.050%; Nb:0.010-0.050%, V:0.020-0.070%, Ti:0.005-0.020%; Cr:0.10-0.30%, surplus is Fe and inevitable impurity;

2) in the roughing operation, start rolling temperature is 1100-1150 ℃, roughing finishing temperature >=1030 ℃; Intermediate blank treats that temperature thickness is finished product thickness 1.5-4.0 times;

3) finish rolling start rolling temperature≤950 ℃, finish rolling finishing temperature≤880 ℃;

4) air cooling after the finish rolling;

5) reheat quenching temperature: 890-930 ℃, tempering temperature 600-650 ℃, soaking time 1.0-2.0H wherein H is a steel plate thickness.