초록 ▼

Method for producing AIMn strip or sheet for making components by brazing and products obtained by said method, in particular fin materials of thin gauge used in heat exchangers. Rolling slabs are produced from a melt with 0.3% Si, ≦0.5% Fe, ≦0.3% Cu, 1.0-2.0% Mn, ≦0.5% Mg, ≦4.0% Zn, ≦0.5% Ni, ≦0.3%

Method for producing AIMn strip or sheet for making components by brazing and products obtained by said method, in particular fin materials of thin gauge used in heat exchangers. Rolling slabs are produced from a melt with 0.3% Si, ≦0.5% Fe, ≦0.3% Cu, 1.0-2.0% Mn, ≦0.5% Mg, ≦4.0% Zn, ≦0.5% Ni, ≦0.3% each of group IVb, Vb, or Vib elements, and unavoidable impurity elements, as well as aluminum that, prior to hot rolling, are preheated at 550° C. to control the number and size of dispersoid particles, hot rolled into a hot strip, cold rolled into a strip with total reduction of at least 90%, and heat treated to obtain a 0.2% proof stress value that is 50-90% of its proof stress value in the as cold rolled condition and in a range between 100 and 200 MPa. The strip may alternatively be produced by twin-roll strip casting.

대표청구항 ▼

1. A sagging resistant strip produced by a) casting a melt comprising: 95% of the core, without intermediate annealing giving recrystallisation of the material, resulting in a strip having a first proof stress value, ande) followed by a heat treatment to the delivery temper with the purpose to softe

1. A sagging resistant strip produced by a) casting a melt comprising: 95% of the core, without intermediate annealing giving recrystallisation of the material, resulting in a strip having a first proof stress value, ande) followed by a heat treatment to the delivery temper with the purpose to soften the material by a tempering without any recrystallisation of the strip alloy,wherein the strip has a second proof stress value which is 10-50% lower than the first proof stress value obtained directly after cold rolling in step d) and a 0.2% proof stress range of 100-200 MPa. 2. A sagging resistant strip according to claim 1, produced by a cold rolling reduction of at least 97.5% of the core without intermediate annealing giving recrystallisation of the material. 3. A sagging resistant strip according to claim 1, wherein said melt comprises: 0.02 to 95% of the core, without intermediate annealing giving recrystallisation of the material resulting in a strip having a first proof stress value, ande) followed by a heat treatment to the delivery temper with the purpose to soften the material by a tempering without any recrystallisation of the strip alloy,wherein the strip has a second proof stress value which is 10-50% lower than the first proof stress value obtained directly after cold rolling in step d) and an absolute proof stress range of 100-200 MPa. 14. A sagging resistant strip according to claim 13, wherein said melt comprises 95% of the core, without intermediate annealing giving recrystallisation of the material resulting in a strip having a first proof stress value, ande) followed by a heat treatment to the delivery temper with the purpose to soften the material by a tempering without any recrystallisation of the strip alloy, to obtain a strip having a second proof stress value which is 10-50% lower than the first proof stress value obtained directly after cold rolling in step d) and lying in the absolute proof stress range of 100-200 MPa. 19. A method according to claim 18, comprising cold rolling to a reduction of at least 97.5% of the core without intermediate annealing giving recrystallisation of the material. 20. A method according to claim 18, wherein said melt comprises: 0.02-95% of the core, without intermediate annealing giving recrystallisation of the material resulting in a strip having a first proof stress value, ande) followed by a heat treatment to the delivery temper with the purpose to soften the material by a tempering without any recrystallisation of the strip alloy, to obtain a strip having a second proof stress value which is 10-50% lower than the first proof stress value obtained directly after cold rolling in step d) and lying in the absolute proof stress range of 100-200 MPa. 31. A method according to claim 30, wherein said melt comprises <0.25 wt % Si. 32. A method according to claim 30, comprising cold rolling to a reduction of at least 97.5% of the core without intermediate annealing giving recrystallisation of the material. 33. A method of producing a sagging resistant strip, comprising: a) twin-roll strip casting a melt comprising: <0.3 wt % Si,≦0.5 wt % Fe,≦0.3 wt % Cu1.0-2.0 wt % Mn,≦0.5 wt % Mg,≦4.0 wt % Zn,≦0.5 wt % Ni,≦0.3 wt % each of dispersoid forming elements from group IVb, Vb, or VIb andunavoidable impurity elements, each at most 0.05 wt %, in a total amount of at most 0.15 wt %,the rest aluminium,so as to obtain a core strip,b) cold rolling the core strip to form an intermediate gauge material,c) annealing the intermediate gauge sheet material so as to form dispersoid particles,d) cold rolling the intermediate gauge article to a finstock material of final gauge with a rolling reduction of at least 60% of the core without intermediate annealing giving recrystallisation of the material, resulting in a finstock material having a first proof stress value, ande) heat treating the finstock material to the delivery temper with the purpose to soften the material by a tempering without any recrystallisation of the strip alloy, to obtain a strip having a second proof stress value which is 10-50% lower than that obtained directly after cold rolling in step d) and lying in the proof stress range of 100-200 MPa, andwherein the method further comprises providing a braze alloy on the as cast core strip either prior to or after said cold rolling to intermediate gauge. 34. A method according to claim 33, wherein said melt comprises <0.25 wt % Si. 35. A heat exchanger comprising fins made from the sagging resistant strip of claim 1. 36. Method of producing fins of a heat exchanger comprising producing a sagging resistant strip according to the method of claim 18 and forming fins from said sagging resistant strip.