CN104233083A - Precipitating strengthened electrothermal alloy and preparation method thereof - Google Patents

Abstract

The invention relates to an electrothermal alloy material, and particularly relates to a precipitating strengthened electrothermal alloy and a preparation method thereof. The precipitating strengthened electrothermal alloy comprises the following elements: C, Si, Mn, Al, Cr, La, Ce, Pr, Y, Ti, N, B, Fe and the like. The preparation method comprises the following processes: burdening; smelting; homogenizing annealing; forging; hot rolling; pickling; rinsing; drying; and multi-pass cold-drawing. The material product prepared by the method has good tensile strength, high-temperature creep strength and inoxidizability, the brittleness of a network carbide is reduced, the defects in the prior art are overcome, and the electrothermal alloy has a good industrial application prospect.

Description

A kind of precipitation strength electrical heating alloys and preparation method thereof

Technical field:

The present invention relates to a kind of electrical heating alloys material, particularly a kind of precipitation strength electrical heating alloys and preparation method thereof.

Background technology:

Electrical heating alloys material is the functional alloy material utilizing the resistance characteristic of material to be heat energy by electric energy conversion, and in metallurgy, machinery, petrochemical industry, electrically, building, military project, household electrical appliances etc. are widely used in manufacturing various electrical heating element in field.At present, electrical heating alloys has developed into a kind of important engineering materials, occupies an important position in national economy.The most frequently used electrical heating alloys is mainly divided into two large classes: have the Aludirome of ferritic structure and have the nichrome of austenite structure.Nichrome resistivity is lower, poor chemical stability, working temperature are low and cost is high, and Aludirome just has series of advantages comparatively speaking, and as allowed, use temperature is high, resistivity is high, high-temperature oxidation resistance is good.But Aludirome is owing to being Alfer, during applied at elevated temperature, ferrite crystal grain is grown up rapidly, alloy high-temp creep strength is declined rapidly, and high temperature creep strength is closest to the stress-strain state of electrical heating element under applied at elevated temperature state, therefore high temperature creep strength declines is the key factor that restriction Aludirome uses.In addition, Aludirome also easily produces (CrFe) 500 DEG C of-800 DEG C of temperature ranges ₂₃c ₆, be net distribution along crystal boundary, make alloy occur obvious fragility, such carbide therefore should be avoided as far as possible to produce.

Summary of the invention:

The object of the invention is to overcome deficiency of the prior art, provide a kind of and adopt precipitation strength mode to improve tensile strength and high temperature creep strength and reduce electrical heating alloys that carbide network produces and preparation method thereof.

A kind of precipitation strength electrical heating alloys, it is characterized in that, elementary composition and the mass percent of described alloy is: C:0.05-0.1%, Si:0.06-0.1%, Mn:0.5-1%, Al:5-7%, Cr:20-25%, La+Ce+Pr+Y:0.1-0.3%, Ti:0.3-0.7%, N≤0.003%, B:0.01-0.02%, S≤0.01%, P≤0.01%, and surplus is iron and inevitable impurity.

In above-mentioned alloying constituent, each element interaction is as follows:

Suitable C element is the main strengthening element of electrical heating alloys, and forms high melting point nm precipitated phase with carbide Ti;

Si element can efficient hardening ferrite stop carburizing, but too high levels can damage alloy plasticity, and content should control at 0.06-0.1%;

Suitable Mn element can improve strength of alloy and high temperature creep property, but Fe content is too high, can damage high-temperature oxidation resistance, and content should control at 0.5-1%;

Al is the most important element of high-temperature oxidation resistance in Aludirome, can improve resistance alloys rate and use temperature simultaneously;

Cr is another important composition element in Aludirome, and Main Function improves resistance of oxidation, raising alloy strength, raising resistivity;

La, Ce, Pr, Y rare earth element can pinning crystal boundary, inhibiting grain growth thus crystal grain thinning, can also promote the generation of protective oxide film simultaneously, thus carry heavy alloyed antioxidant property;

Ti, as carbide, is combined with C element and generates high melting point nm precipitated phase TiC, plays effective strengthening effect on the one hand; Grain growth when simultaneously effectively can also stop high temperature, crystal grain thinning, improves high temperature creep strength; Last carbide Ti can ensure preferentially to be combined with C, thus avoids producing netted (CrFe) ₂₃c ₆, reduce alloy fragility; Finally, remaining Ti generates TiO when high temperature, the Al on alloy surface ₂o ₃oxide film has strengthening effect, can improve compactness and the strippability of oxide film;

N element, be mingled with for avoiding the formation of large-sized TiN, alloy performance causes disadvantageous effect, should strictly control N content and be less than 30ppm;

Meanwhile, add appropriate B, also can play the effect of good fix N, in addition all right effectively pin crystal boundary of B, crystal grain thinning.

The preparation method of described precipitation strength electrical heating alloys, is characterized in that, described preparation method comprises:

(1) prepare burden: prepare burden according to following composition: C:0.05-0.1%, Si:0.06-0.1%, Mn:0.5-1%, Al:5-7%, Cr:20-25%, La+Ce+Pr+Y:0.1-0.3%, Ti:0.3-0.7%, N≤0.003%, B:0.01-0.02%, S≤0.01%, P≤0.01%, surplus is iron and inevitable impurity;

(2) melting: above-mentioned raw materials is put into vacuum induction melting furnace, vacuumize and be filled with high-purity argon gas protection, after melting, furnace cooling becomes alloy pig;

(3) homogenizing annealing: alloy pig is put into vacuum heat treatment furnace, is heated to 1100 DEG C-1200 DEG C insulations 24 hours;

(4) forge: sample after homogenizing annealing come out of the stove and forges immediately, being forged into size Φ 40mm pole and air cooling;

(5) hot rolling: the pole after forging is heated to 1200 DEG C-1300 DEG C, and be incubated 2 hours, hot rolling of coming out of the stove is Φ 5mm wire rod, and finishing temperature 900-950 DEG C rolls rear air cooling to room temperature;

(6) cold-drawn Cheng Sicai after gren rod pickling, rinsing also being dried, Φ 5mm wire rod is worked into Φ 2-3mm by first time cold-drawn, second time cold-drawn is worked into Φ 0.5-1mm, third time cold-drawn be worked into Φ 0.08-0.1mm, between every time cold-drawn by silk material at 800-850 DEG C of softening annealing 2h;

(7) after cold-drawn silk material through weak acid pickling, rinsing and dry become finished product.

Embodiment:

Set forth further below by embodiment and understand the present invention.

The element proportioning of embodiment 1-3 is as shown in table 1.

The element proportioning (wt%) of table 1 embodiment 1-3

Alloy	C	Si	Mn	Al	Cr	La	Ce	Pr	Y	Ti	N	B	S	P	Fe
																1	0.05	0.071	0.65	5.6	21.2	0.02	0.04	0.04	0.03	0.35	0.002	0.01	0.005	0.007	Surplus
2	0.07	0.082	0.81	6.3	23.5	0.04	0.03	0.05	0.06	0.49	0.002	0.02	0.004	0.005	Surplus
																3	0.10	0.077	0.89	6.9	24.1	0.05	0.07	0.06	0.04	0.64	0.003	0.02	0.004	0.006	Surplus

(1) prepare burden: prepare burden according to the element proportioning in table 1;

(2) melting: above-mentioned raw materials is put into vacuum induction melting furnace, vacuumize and be filled with high-purity argon gas protection, after melting, furnace cooling becomes alloy pig;

(3) homogenizing annealing: alloy pig is put into vacuum heat treatment furnace, is heated to 1150 DEG C of insulations 24 hours;

(4) forge: sample after homogenizing annealing come out of the stove and forges immediately, being forged into size Φ 40mm pole and air cooling;

(5) hot rolling: the pole after forging is heated to 1250 DEG C, and be incubated 2 hours, hot rolling of coming out of the stove is Φ 5mm wire rod, and finishing temperature 950 DEG C rolls rear air cooling to room temperature;

(6) cold-drawn Cheng Sicai after gren rod pickling, rinsing also being dried, Φ 5mm wire rod is worked into Φ 2.4mm by first time cold-drawn, second time cold-drawn be worked into Φ 0.8mm, third time cold-drawn be worked into Φ 0.09mm, between every time cold-drawn by silk material at 820 DEG C of softening annealing 2h;

(7) cold-drawn nichrome wire is also dried through weak acid pickling, rinsing becomes finished product.

Alloy finished product prepared by embodiment of the present invention 1-3 has higher room temperature resistivity, tensile strength, unit elongation and oxidation-resistance, overcomes deficiency of the prior art, has wider prospects for commercial application.Concrete test data is as follows:

Table 2 room temperature resistivity (Ω mm ²/ m)

Alloy	1	2	3	0Cr25Al5
					Resistivity	1.89	1.94	2.01	1.43

Table 3 tensile strength (MPa) and unit elongation (%)

Alloy	1	2	3	0Cr25Al5
					Tensile strength	884	972	1080	780
Unit elongation	14.7	14.1	14.9	12.1

Table 4 Oxidation Resistance Test

Alloy	Temperature (DEG C)	Oxidization time (h)	Weightening finish (mg/cm 2)
				1	1200	300	3.03
2	1200	300	2.95
				3	1200	300	2.81
0Cr25Al5	1200	300	3.38

Obviously, above-described embodiment is only for example of the present invention is clearly described, and is not the restriction to embodiments of the present invention.For those of ordinary skill in the field, can also make other changes in different forms on the basis of the above description.Here exhaustive without the need to also giving all embodiments.And these belong to spirit institute's apparent change of extending out of the present invention or change and are still among protection scope of the present invention.

Claims (2)

1. a precipitation strength electrical heating alloys, it is characterized in that, elementary composition and the mass percent of described alloy is: C:0.05-0.1%, Si:0.06-0.1%, Mn:0.5-1%, Al:5-7%, Cr:20-25%, La+Ce+Pr+Y:0.1-0.3%, Ti:0.3-0.7%, N≤0.003%, B:0.01-0.02%, S≤0.01%, P≤0.01%, and surplus is iron and inevitable impurity.

2. the preparation method of a kind of precipitation strength electrical heating alloys as claimed in claim 1, it is characterized in that, described preparation method comprises:

(1) prepare burden: prepare burden according to following composition: C:0.05-0.1%, Si:0.06-0.1%, Mn:0.5-1%, Al:5-7%, Cr:20-25%, La+Ce+Pr+Y:0.1-0.3%, Ti:0.3-0.7%, N≤0.003%, B:0.01-0.02%, S≤0.01%, P≤0.01%, surplus is iron and inevitable impurity;

(2) melting: above-mentioned raw materials is put into vacuum induction melting furnace, vacuumize and be filled with high-purity argon gas protection, after melting, furnace cooling becomes alloy pig;

(3) homogenizing annealing: alloy pig is put into vacuum heat treatment furnace, is heated to 1100 DEG C-1200 DEG C insulations 24 hours;

(4) forge: sample after homogenizing annealing come out of the stove and forges immediately, being forged into size Φ 40mm pole and air cooling;

(5) hot rolling: the pole after forging is heated to 1200 DEG C-1300 DEG C, and be incubated 2 hours, hot rolling of coming out of the stove is Φ 5mm wire rod, and finishing temperature 900-950 DEG C rolls rear air cooling to room temperature;

(6) cold-drawn Cheng Sicai after gren rod pickling, rinsing also being dried, Φ 5mm wire rod is worked into Φ 2-3mm by first time cold-drawn, second time cold-drawn is worked into Φ 0.5-1mm, third time cold-drawn be worked into Φ 0.08-0.1mm, between every time cold-drawn by silk material at 800-850 DEG C of softening annealing 2h;

(7) after cold-drawn silk material through weak acid pickling, rinsing and dry become finished product.