CN103614594B

CN103614594B - A kind of method eliminating refractory alloy hot-work surface folding

Info

Publication number: CN103614594B
Application number: CN201310664243.0A
Authority: CN
Inventors: 刘正东; 陈正宗; 包汉生; 杨钢; 干勇
Original assignee: Central Iron and Steel Research Institute
Current assignee: Central Iron and Steel Research Institute
Priority date: 2013-12-09
Filing date: 2013-12-09
Publication date: 2015-08-26
Anticipated expiration: 2033-12-09
Also published as: CN103614594A

Abstract

Eliminate a method for refractory alloy hot-work surface folding, belong to refractory alloy technical field of hot working.The technical parameter controlled in technique is: want strict lower control limit hot processing temperature during tubulation base jumping-up, described lower limit hot processing temperature is 1050 ~ 1100 DEG C, and upper limit hot processing temperature is 1200 DEG C ~ 1230 DEG C; To jacket be carried out during base, when the object of jacket is jumping-up, before outer metallic surface contact squeeze barrel, limit metal flow; Sheath material is carbon steel or stainless steel, thickness 3-5mm.To be applicable in elimination 700 DEG C of vapor temperature ultra supercritical coal-fired unit refractory alloy pipeline base processes due to the surface folding defect that non-recrystallization or partial recrystallisation cause, surface quality when improving base, improves alloy lumber recovery, reduces production cost.

Description

A kind of method eliminating refractory alloy hot-work surface folding

Technical field

The invention belongs to refractory alloy technical field of hot working, particularly relate to a kind of method eliminating refractory alloy hot-work surface folding, be applicable in elimination 700 DEG C of vapor temperature ultra supercritical coal-fired unit refractory alloy pipeline base processes due to surface folding defect that non-recrystallization or partial recrystallisation cause, surface quality when improving base, improve alloy lumber recovery, reduce production cost.

Technical background

The manufacturing technology of China's 600 DEG C of ultra supercritical power station large-diameter pipes is mature on the whole, and vertical extrusion technique production specification can be utilized for Φ 273 ~ 1066mm, the steel pipe of wall thickness 20 ~ 130mm.700 DEG C of extra-supercritical unit can energy-saving and emission-reduction further, and China has set up 700 DEG C of coal-fired thermal power generating technology Innovation Alliances of advanced ultra supercritical, puts forth effort on construction 700 DEG C of ultra supercritical Demonstration Stations.600 DEG C of ultra supercritical power station thick-wall and large-diameter tubes are Ascalloy, can not be applied to 700 DEG C, and Refractoloy must be selected to manufacture thick-wall and large-diameter tube.Compared with Ascalloy, Refractoloy resistance to deformation is large, and thermal processing distortion temperature range is narrow, the distortion of large size ingot shape difficulty.

At present, heavy wall bigbore Hot-extrusion in power station is ripe, and solves 600 DEG C of ultra supercritical station boiler external diameter Φ 273 ~ 1066mm, the manufacture of wall thickness 20 ~ 130mm heavy caliber thick wall seamless steel tube.The production technique of Ascalloy large-diameter steel pipe mainly adopts vertical extrusion technique with manufacture method, refers to patent CN101706019 B ^[1].And poorer than the deformability of iron for Refractoloy, recrystallization temperature is high, in base process, easily occur fold.Once there is fold, just need a large amount of machinings to eliminate the fold on alloy pipe stock, if serious fold cannot be eliminated, compo pipe will be made to scrap.Namely allow to eliminate fold, too increase the compo pipe production cycle, reduce efficiency, also result in raw-material consumption simultaneously, reduce compo pipe lumber recovery.

The invention provides a kind of method eliminating refractory alloy hot-work surface folding, improve refractory alloy tube-surface quality, improve refractory alloy lumber recovery, reduce the manufacturing cost of refractory alloy pipe.

Summary of the invention

The object of the invention is to provide a kind of method eliminating refractory alloy hot-work surface folding, solves the hot-work surface folding problem of existing refractory alloy, improves refractory alloy large-calibre seamless tubing lumber recovery, reduces material manufacturing cost.Be applicable to the parts such as 700 DEG C of vapor temperature ultra supercritical coal-fired unit heavy caliber thick wall boiler tubings and pipe fitting.

The present invention, by restriction refractory alloy lower limit texturing temperature, utilizes jacket to limit surface of steel ingot side direction metal flow simultaneously, can eliminate refractory alloy hot-work surface folding defect.

Refractory alloy chemical composition (% by weight) of the present invention is as follows: Cr21 ?23%; Fe < 1.0%; C0.03 ?0.08%; Mn≤0.5%; Si≤0.25%; Co11 ?13%; Mo8.0 ?10.0%; Ti0.3 ?0.5%; Al0.8 ?1.3%; Cu≤0.15%; P < 0.012%; S < 0.008%; B0.002 ?0.005%; Nb≤1.0%; V≤0.6%; W < 2.0%; N≤0.015%; Ca≤0.01%; Zr≤0.02%; Surplus is nickel and inevitable impurity element.

The present invention is applicable to the refractory alloy of mentioned component, and the technical parameter controlled in its technique is as follows:

(1) want strict lower control limit hot processing temperature during tubulation base jumping-up, described lower limit hot processing temperature is 1050 ~ 1100 DEG C, and upper limit hot processing temperature is 1200 DEG C ~ 1230 DEG C.

(2) to jacket be carried out during base, when the object of jacket is jumping-up, before outer metallic surface contact squeeze barrel, limit metal flow; Sheath material is carbon steel or stainless steel, thickness 3-5mm.

Principle of the present invention: refractory alloy recrystallization temperature of the present invention is high, resistance to deformation is large, and hot processing temperature window narrows, its hot ductility curve as shown in Figure 1.There is " muscle shape " surface folding phenomenon when 1050 DEG C of hot compress test in refractory alloy, as Fig. 2; Also surface folding phenomenon is there is, as shown in Figure 3 when carrying out hot tensile test lower than less than 1100 DEG C.In the present invention, this phenomenon is analyzed, high-temperature homogenization diffusion annealing process when Refractoloy will carry out long before hot-work, column crystal in ingot casting coarse grains after high-temperature homogenization diffusion annealing when long, and CRYSTALLITE SIZES is uneven, as shown in Figure 4.During thermo compression, surface folding metallographicobservation finds, grain size is uneven, and grain boundaries generation local dynamic station recrystallize, recrystal grain is tiny.The reason schematic model of surface folding metallographicobservation and formation respectively as shown in Figure 5 and Figure 6.Recrystallization is easily formed at high dislocation density place, such as crystal boundary.After grain boundaries forms recrystal grain, intensity reduces, and show as softening, intracrystalline intensity, higher than grain-boundary strength, is out of shape and is carried out along crystal boundary.When blank pressurized, central metal flows to both sides, and the large grain size of edge forms rat due to crystal boundary partial recrystallisation, and little crystal grain due to compatibility of deformation ability weak, form surface recessed, just form surface folding at large and small crystal grain joint like this.

The technology used in the present invention solution is:

1., during the hot-work first of the ingot shape when long after High temperature diffusion homogenizing annealing, strict lower control limit thermal processing distortion temperature, texturing temperature is higher than 1100 DEG C.

2. when suitability for industrialized production carries out jumping-up base, while lower control limit texturing temperature, use carbon steel jacket at blank outside surface, the object of jacket is to jumping-up limit metal flow, eliminates the generation of surface folding.The present invention uses carbon steel or stainless steel jacket, thickness 3 ~ 5mm.

Compared with prior art, the invention has the beneficial effects as follows: improve pipe surface quality, is the hollow billet that subsequent extrusion pipe provides surface good; Improve refractory alloy seamless tube lumber recovery, reduce material cost.

Accompanying drawing explanation

Fig. 1 refractory alloy hot ductility curve of the present invention.

Macro surface fold during the 1050 DEG C of deformation heat compressions of Fig. 2 refractory alloy of the present invention.In figure be successively from left to right 1050 DEG C of strain rates respectively 0.01,0.1,1,10S ^-1surface folding phenomenon during distortion.

Fig. 3 refractory alloy of the present invention is lower than 1100 DEG C of thermal stretch macro surface folds.

Fig. 4 refractory alloy of the present invention is horizontal metallographic structure (50 ×) after high-temperature homogenization diffusion annealing.

Surface folding section metallographicobservation during Fig. 5 refractory alloy thermo compression of the present invention.

It is (left: before compression that Fig. 6 surface folding produces schematic model; In: partial recrystallisation forms surface folding; Right: without surface folding).

Fig. 7 refractory alloy of the present invention 1000 DEG C and 1150 DEG C thermal stretch sample macro surface are (upper: 1000 DEG C; Under: 1150 DEG C).

Embodiment

Embodiment 1:

Adopt 50Kg vacuum induction furnace smelting refractory alloy ingot of the present invention, when carrying out long after high-temperature homogenization diffusion annealing, utilize thermal simulation machine to carry out 1000 ~ 1200 DEG C of thermo compression and hot tensile test, carry out macro surface observation.Result shows, and surface folding appears in the sample deformation district lower than 1100 DEG C of texturing temperatures, and temperature is lower, and fold is more serious; The distorted area smooth surface of 1100 ~ 1190 DEG C of interval samples of texturing temperature; When 1200 DEG C, thermal stretch display thermoplasticity sharply reduces.

Embodiment 2:

Utilize 200Kg vacuum induction furnace smelting refractory alloy ingot two of the present invention stove, after steel ingot vehicle light, billet is of a size of Ф 200mm, high 300mm, high-temperature homogenization diffusion annealing when carrying out long, then jumping-up, wherein a stove strict lower control limit texturing temperature carries out 3mm carbon steel jacket higher than 1100 DEG C, and after jumping-up, cooling is observed without surface folding; And another stove example as a comparison, upsetting process temperature, at about 1050 DEG C, without jacket process, observes surface folding serious after cooling.The serious comparative example of surface folding needs the thicker one deck of turning, and its turning amount of metal is 3 times without surface folding example turning amount of metal.

Embodiment 3:

Industry trial-production: adopt vacuum induction to smelt VIM+ vacuum consumable VAR remelting 5.5 tons of refractory alloy ingots of the present invention, utilize certain company 1.5 ten thousand tons of blank machine bases, preforming comprises container jumping-up and punching.Base process is as follows: by No. 45 thick for surface of steel ingot integument 4mm steel plates, joint welds, and steel ingot two circle cross section does not wrap up, outside surface metal flow when object is restriction jumping-up.Steel ingot shove charge is carried out high temperature long time homogenizing diffusion annealing after, take out, roller coating glass lubricant on roller coating platform, put into the jumping-up cylinder mould jumping-up of preheating, Upsetting temperature is higher than 1100 DEG C, and after jumping-up, mobile blank machine patrix switching mechanism, directly carries out punching.Observe after hollow billet cooling, except surface residual glass lubricant etc., surface quality is good, without surface folding.

Claims

1. eliminate a method for refractory alloy hot-work surface folding, the Ingredients Weight % being applicable to refractory alloy is: Cr 21-23%; Fe < 1.0%; C 0.03-0.08%; Mn≤0.5%; Si≤0.25%; Co 11-13%; Mo 8.0-10.0%; Ti 0.3-0.5%; Al 0.8-1.3%; Cu≤0.15%; P < 0.012%; S < 0.008%; B 0.002-0.005%; Nb≤1.0%; V≤0.6%; W < 2.0%; N≤0.015%; Ca≤0.01%; Zr≤0.02%; Surplus is nickel and inevitable impurity element; It is characterized in that, the technical parameter controlled in technique is as follows:

(1) want strict lower control limit hot processing temperature during tubulation base jumping-up, described lower limit hot processing temperature is 1100 DEG C, and upper limit hot processing temperature is 1200 DEG C ~ 1230 DEG C;

(2) to jacket be carried out during base, make before outer metallic surface contact squeeze barrel, to limit metal flow during jumping-up; Sheath material is carbon steel or stainless steel, thickness 3-5mm.