阅读说明：本技术 生产耐腐蚀和耐高温材料的方法 (Method for producing corrosion-resistant and high-temperature-resistant material ) 是由 A.埃斯佩达尔 X-J.蒋 M.李 于 2020-04-29 设计创作，主要内容包括：本发明涉及一种生产耐腐蚀铝合金挤出件的方法,所述挤出件由具有下列组成的合金构成≤0.30,优选0.05-0.15重量%的硅,≤0.40,优选0.06-0.35重量%的铁,0.01-1.1重量%的锰,≤0.30,优选0.15-0.30重量%的镁,≤0.70,优选0.05-0.70重量%的锌,≤0.35,优选0.25重量%的铬,≤0.20重量%的锆,≤0.25,优选0.05-0.25重量%的钛,≤0.20重量%钒≤0.10重量%的铜最多0.15重量%的其它杂质,各自不大于0.03重量%和余量铝,所述方法包括步骤a)将熔融金属铸造成挤出坯料b)对所述坯料施以在550至620℃的保持温度下的均匀化处理6至10小时c)将所述坯料加热到400至550℃的温度d)将所述坯料挤出成管材。(The invention relates to a method for producing a corrosion-resistant aluminum alloy extrusion consisting of an alloy having the following composition ≦ 0.30, preferably 0.05-0.15 wt.% silicon, ≦ 0.40, preferably 0.06-0.35 wt.% iron, 0.01-1.1 wt.% manganese, ≦ 0.30, preferably 0.15-0.30 wt.% magnesium, ≦ 0.70, preferably 0.05-0.70 wt.% zinc, ≦ 0.35, preferably 0.25 wt.% chromium, ≦ 0.20 wt.% zirconium, ≦ 0.25, preferably 0.05-0.25 wt.% titanium, ≦ 0.20 wt.% vanadium ≦ 0.10 wt.% copper, up to 0.15 wt.% of other impurities, each not more than 0.03 wt.% and the balance aluminum, the method comprises the steps of a) casting molten metal into an extruded billet b) subjecting the billet to a homogenization treatment at a holding temperature of 550 to 620 ℃ for 6 to 10 hours c) heating the billet to a temperature of 400 to 550 ℃ d) extruding the billet into a tube.)

1. A method of producing a corrosion resistant aluminum alloy extrusion comprised of an alloy having the following composition

0.30% by weight or less, preferably 0.05 to 0.15% by weight, of silicon,

0.40% or less, preferably 0.06 to 0.35% by weight, of iron,

0.01-1.1% by weight of manganese,

less than or equal to 0.30, preferably from 0.15 to 0.30,% by weight of magnesium,

0.70% by weight or less, preferably 0.05 to 0.70% by weight, of zinc,

0.35% by weight or less, preferably 0.25% by weight, of chromium,

less than or equal to 0.20 weight percent of zirconium,

less than or equal to 0.25, preferably from 0.05 to 0.25,% by weight of titanium,

less than or equal to 0.20 weight percent of vanadium

Less than or equal to 0.10 weight percent of copper

Up to 0.15 wt.% of other impurities, each not more than 0.03 wt.% and

balance aluminum, said method comprising the steps of

a) The molten alloy is cast into an extruded billet,

b) subjecting the billet to a homogenization treatment at a holding temperature of 550 to 620 ℃ for 6 to 10 hours,

c) heating the billet to a temperature of 400 to 550 ℃,

d) extruding the billet into a tube.

2. The process according to claim 1, wherein the extruded tube is annealed by heating to 400 to 480 ℃ and holding for 0 to 3 hours, preferably 1 to 3 hours.

3. The method according to claim 1, wherein said extrusion is a porous extrusion, an extruded straight reinforced tube or a base tubing for PDT and/or a helically internally threaded tube.

4. A method according to claim 1 or 2, characterized in that the alloy contains 0.30-0.60 wt.%, more preferably 0.4-0.5 wt.% manganese.

5. A method according to any one of the preceding claims, characterized in that the alloy contains 0.15-0.20 wt.% Zn.

6. A process according to any one of the preceding claims, characterized in that it contains 0.10-0.30% by weight of zinc.

7. A method according to any one of the preceding claims, characterized in that the alloy contains 0.08-0.13 weight-% silicon.

8. A method according to any one of the preceding claims, characterized in that the alloy contains 0.06-0.18 weight% iron.

9. A method according to any one of the preceding claims, characterized in that the alloy contains 0.05-0.15 weight-% chromium.

10. A method according to any one of the preceding claims, characterized in that the alloy contains 0.02-0.20% by weight of zirconium.

11. A method according to any one of the preceding claims, characterized in that the alloy contains 0.10-0.25% by weight titanium.

12. A method according to any one of the preceding claims, wherein the copper content is below about 0.01% by weight.

13. An aluminum extrusion made by the method of claims 1-10, wherein the extrusion is further coated with zinc.

14. An aluminum extrusion made by the process of claim 13 wherein the tubing can be zinc arc sprayed after extrusion or drawing to prevent corrosion and the average zinc loading can be 3g/m2 to 10g/m 2.

15. Use of an aluminium extrusion according to claim 13 or 14 in a heat exchanger.

Summary of The Invention

It is an object of the present invention to provide a method of producing an extrudable, drawable and brazable aluminum extrusion having improved corrosion resistance and suitable for use in thin-walled fluid conveying conduits. It is another object of the present invention to provide an aluminum alloy tube for heat exchanger applications. It is a further object of the present invention to provide an aluminum alloy having improved formability during bending and end forming operations.

The present invention provides an aluminum extrusion having excellent extrusion resistance, drawability, formability, high strength, good brazeability and excellent corrosion resistance for use in automotive piping, solar collectors, large mpe (macro mpe), internally threaded pipes (straight reinforced and internal screw threads).

Detailed Description

The invention will now be described in more detail with reference to the accompanying drawings:

FIG. 1 is a process flow chart for manufacturing an aluminum alloy pipe

Figure 2 corrosion results of tube a according to the invention and a standard AA3003 alloy tube tested in SWAAT (16X 1.6 mm, O temper). SWAAT test is according to ASTM G85-A3.

FIG. 3 Process route for porous Extrusion (Multi Port Extrusion), porous Extrusion + Zinc Arc Spray (ZAS) or porous Extrusion + Hybraz coating.

FIG. 4 Process route for extruding straight reinforced pipes (+ ZAS).

The chemical composition of the blank was determined by means of emission spectroscopy.

The composition of the alloy used in the present invention is given in table 1.

The manufacturing process for producing extruded tubing is described in the following paragraphs.

Alloying elements were added to the melting furnace to obtain molten metals having the alloy chemistries shown in table 1. The molten metal is cast into an extruded billet. The billet is subjected to a homogenization treatment at a holding temperature of 550 to 620 ℃ for 6 to 10 hours. The purpose of this heat treatment is to soften the billet to extrude it through the die and to reach sufficient temperature and achieve mechanical properties. If the temperature is too low, the blank is too stiff to push through the press and may damage the die. If the temperature is too high, the surface quality of the profile is poor and the extrusion speed must be reduced. The blank is then allowed to cool, preferably to a predetermined temperature below 550 deg.C, such as 380-480 deg.C or to room temperature, i.e., about 20 deg.C. Thereafter, the billet is heated to a temperature of 400 to 550 ℃ to achieve the temperature required for extrusion. If the temperature is too low, the billet is too hard to be ejected, and if the temperature is too high, pipe surface defects such as pickup, web tearing (web) occur.

The billet is then extruded into a Multi-Port Extrusion (Multi Port Extrusion), extruded straight reinforced tube (extruded straight reinforced tube), or base tubing for precision drawn tubes and/or helically internally threaded tubes, depending on the application.

A process flow diagram for manufacturing an aluminium alloy pipe is shown in figure 1.

The billet is preheated to a temperature of 450 to 500 ℃ prior to extrusion into a tube at 60 to 120 ℃/meter taper (taper) (temperature gradient along the length of the billet), the die is preheated to 450 to 550 ℃ and soaked for 2 to 10 hours prior to use. The extrusion discharge (runout) speed of the pipe was controlled to 40 to 100 m/min to obtain a good quality pipe surface. The extruded tubing may be coiled during extrusion and may be extruded into straight tubes. The pipe is preferably cooled by quenching as quickly as possible upon exiting the press. The discharge temperature should preferably be controlled to below 590 ℃ to achieve optimal microstructure, surface quality and mechanical properties.

The base tubing can be drawn to different sizes through different outer diameters and wall thinnings. Drawn tubing can be made into H112, H12, H14, H18 tempers and can be annealed to O tempers after drawing. The preferred annealing process is heating to 400 to 480 ℃ and holding for 0 to 3 hours, preferably 1 to 3 hours. Annealing for 0 hours means that the tubes are placed in a furnace before the annealing temperature is reached and they are removed when the desired temperature is reached.

After extrusion and drawing, the pipe can be coated with zinc, for example by arc spraying, to prevent corrosion. The average zinc loading can be 3g/m2 to 10g/m 2. The pipe with the zinc coating needs to be exposed to a diffusion heat treatment before being shipped. The heat treatment is carried out by heating the pipe to 300 to 600 ℃ and soaking for 2 to 10 hours. The diffusion depth of zinc into the tube wall can be 100um to 300 um.

To demonstrate the improved corrosion resistance of the inventive aluminum alloy extrusions compared to known prior art materials, the corrosion resistance was tested using the so-called SWAAT test (sea water acetic acid test). The test was performed according to ASTM G85 annex A3 with alternating 30 minute spray periods and 90 minute soak periods above 98% relative humidity. The electrolyte used was artificial seawater acidified with acetic acid to pH 2.8 to 3.0 and having a composition according to ASTM standard D1141. The temperature in the chamber was maintained at 49 ℃. The test was run in an Ascott salt spray chamber. In fig. 2 it can be seen that the drawn tube of type a alloys (Si 0.10, Fe 0.12, Cu 0.00, Mn 0.46, Mg 0.18, Cr 0.07, Zn 0.22, Ti 0.13) made by the method according to the invention has a much higher corrosion resistance than a typical AA3003 alloy extrusion.

The electrical conductivity of the extruded billet after homogenization is given in table 2. Measurements were made according to ASTM E1004 Electrical (Eddy-Current) Measurements of Electrical Conductivity to confirm that the heat treatment process was properly performed.

The mechanical properties of the final tube according to the invention in O/H111 temper and brazed are shown in table 3:

annealing	O/H111	Brazing of
			Yield strength Rp0.2 [MPa]	min. 40	min. 35
Tensile Strength Rm [MPa]	min. 85	min. 80
			Elongation A5 [% ]]	min. 30	min. 25

Value after brazing depends on the brazing cycle

Table 3.

These objects and advantages are achieved by an aluminum-based alloy consisting of 0.05-0.15 wt.% silicon, 0.06-0.35 wt.% iron, 0.01-1.10 wt.% manganese, 0.15-0.30 wt.% magnesium, 0.05-0.70 wt.% zinc, 0-0.25 wt.% chromium, 0-0.20 wt.% zirconium, 0-0.25 wt.% titanium, 0-0.10 wt.% copper, up to 0.15 wt.% of other impurities (each no more than 0.03 wt.%) and the balance aluminum.

The manganese content should be 0.01-1.10 wt.%, preferably 0.30-0.60 wt.%, more preferably 0.40-0.50 wt.%. The addition of manganese contributes to the strength, but the emphasis is on mitigating the negative effects of manganese on manganese-containing phase precipitation during the final anneal, which contributes to coarser final grain sizes.

The addition of magnesium in the range of 0.05-0.30 wt.%, preferably 0.15-0.30, most preferably 0.15-0.20 wt.%, results in a refinement of the final grain size (due to storing more energy for recrystallization during deformation) and an improvement in the strain hardening capacity of the material. In general, this means improved formability during e.g. bending and end forming of tubing. Magnesium also has a positive influence on the corrosion properties by changing the oxide layer. The magnesium content is preferably less than 0.3 wt% because of its strong effect on improving extrudability. Additions above 0.3 wt.% are generally incompatible with good brazeability.

Considering the contaminating effect of zinc (even small zinc concentrations adversely affect the anodization properties of AA 6000-series alloys), the content of this element should be kept low to make the alloy more recyclable and cost-effective in the foundry (cast house). On the other hand, zinc has a strong positive effect on corrosion resistance and may be added up to 0.70 wt.%, but for the reasons given above, the amount of zinc is preferably 0.05-0.70 wt.%, more preferably 0.10-0.30 wt.%.

The iron content of the alloy according to the invention is preferably 0.40% by weight or less, preferably 0.06 to 0.35% by weight. In general, a low iron content, preferably 0.06-0.18 wt.%, is desirable for improving corrosion resistance because it reduces the amount of iron-rich particles that typically establish pitting attack sites. However, too low an amount of iron is difficult from a foundry perspective and also has a negative impact on the final grain size (due to less iron-rich particles acting as nucleation sites for recrystallization). To counter the negative effects of the relatively low iron content in the alloy, other elements may be added for grain structure refinement.

The silicon content is 0.30% by weight or less, preferably 0.05 to 0.15% by weight, more preferably 0.08 to 0.13% by weight. It is important to keep the silicon content within these limits to control and optimize the particle size distribution of the AlFeSi-type particles (primary and secondary) and thus to control the grain size in the final product.

It is desirable to add some chromium to the alloy in order to improve corrosion resistance. However, the addition of chromium increases the extrudability and adversely affects the drawability of the pipe, and therefore is used in an amount of 0.35% by weight or less, 0.05 to 0.25% by weight, more preferably 0.05 to 0.15% by weight.

For optimum corrosion resistance, the zirconium content should be 0.20% by weight or less, preferably 0.02 to 0.20% by weight, more preferably 0.10 to 0.18% by weight. Within this range, any change in the amount of zirconium hardly affects the extrudability of the alloy.

Further optimization of the corrosion resistance can be achieved by adding titanium in an amount of 0.20% by weight or less, preferably 0.05 to 0.25% by weight, more preferably 0.10 to 0.15% by weight. No significant effect on extrudability was found at these titanium levels.

The copper content of the alloy should be kept as low as possible and 0.10% by weight or less, preferably below 0.01% by weight, due to the strong negative influence on the corrosion resistance and due to the negative influence on the extrudability even at small addition levels.

The mechanical properties of the annealed pipes were tested on a Zwick Z100 tensile tester according to the NS-EN-ISO 6892-1-B standard. In the test, the E modulus was set to 70000N/mm 2 throughout the test. The test speed was constant at 10N/mm 2 per second until YS (yield strength) was reached, whereas the test from YS until fracture occurred was 40% Lo/min, Lo being the initial gauge length (initial gauge length).

The results show that the aluminium alloy extrusions made with the method of the present invention provide significantly better corrosion resistance than aluminium extrusions made according to standard procedures.

It was found that during extrusion of the different alloys, extrusion pressures equal to or up to 5-6% higher were obtained for the tested alloys than for the 3103 reference alloy. This is considered a small difference and it should be noted that all alloys run at the same billet temperature and press speed (no press parameter optimization was done in this test).

Post-extrusion surface finish, especially inside pipes, is of particular importance in this application because the pipes are cold drawn to smaller diameters and wall thicknesses. Surface defects may interfere with the drawing process and cause the pipe to break during the drawing process. All alloys studied during the test showed good internal surface appearance.