United States Patent HEAT TREATMENT

United States Patent HEAT TREATMENT OF ALUMINUM ALLOYS Otto Schaaber, Schorndorf, Germany Al-Mg-Si type as long as they do not contain substantial quantities of copper. The amount of copper suppressing the detrimental efiect of room temperature storage varies but is to a certain degree proportional to the amount 01 5 MgzSi present. No Drawing. Application May 6, 1949, It is an object of this invention to provide a novel Serial No. 91,861 pflocess fwtlkllichhwill permit the artificial gging off a oys o e a ove type to pro uce pro ucts o o y 4 Clams improved mechanical properties.

The present invention relates to a novel artificial age It is a further object to provide a novel process which hardening treatment for age hardenable aluminum alloys will increase the corrosion resistance to artificially aged which undergo spontaneous age hardening at room tem- -Mgy peratures to the detriment of subsequently performed Still another ob ect of the invention 1s to provide a artificial aging treatments. More particularly the invenpr e the heat treatment of alloys which tion relates to the treatment of aluminum alloys whose W111 Petmlt subsequent artificial g hardening to Produce principal alloying elements are magnesium and silicon in eXeellent mechanlcal properties even though such alloys approximately the stoichiometric proportion of MgzSi a stored at room temperature between the time y and wherein the proportion f Mggsi i between 05% are subjected to solution heat treatment and the artificial and 3.0% and containing no more than about 0.3% of aglng treatmentcopper and preferably not more than 0.1% of copper. It Was fohnd galloys even When quenched These Al-Mg-Si alloys may also contain silicon in excess from a solution heat treatment in water at 20 C. and. of the stoichiometric proportion MgzSi, manganese in e labesatory conditions, immediately subjected tn amounts up to 1.5% and not more than a total f 1.0% artificial aging at elevated temperatures do not achieve of other alloying element h as for l copper as favorable mechanical properties as those achieved by less than 0.3% preferably less than 0.1%, Zn less than h Process In accoi'danee With the inventiohp 0.5%, Cr less than 0.5% and Fe less than 0.5%. Alloys trons p eemmerelal scale it is not practically p of the following composition are especially suitable for slhle t0 subleet e alloys t0 artificial aging at elevated treatment in accordance with the invention; Mg 0.3% P as qnlekly as is Possible in Operations 011 a to 15% preferably 07% t 10%, Si 01% t 15% laboratory scale and usually at least above five minutes preferably 0.7% to 1.2%, Mn less than 1.5% preferably Intervene between t quenching and the artificial aging between 0.6% t 10% C l h 03% preferably l In accordance with the invention it has been discovered h 01%, Z l h 03%, C l h 03%, i that substantial advantages are obtained when Al-Mg-Sl' less than 0.5% and the remainder substantially aluminum. alloys a q e from a uti n heat treatment in a Alloys of thi ty are ll bj t d to a l quenching medlum which is maintained at the tempera- 'tion heat treatment at 520 to 570 C. and are then tine required for the artificial aging of the alloys namely quenched and subsequently aged either at room tembetween ahd p y between perature or artificially aged at temperatures between 120 a and are maintained at such temperature and 200 0. preferably 140 to 160 c. to improve their untll deslretl Properties of the alley are produced. mechanical properties. When such alloys are aged at The tlme Q WhlQh the alloy is maintained depends uP011 room temperatures the following average mechanical 40 h prepertles which are sought in the y- The artifiproperties are obtained in the alloys: yield strength elal aglng y be Completed Without Permitting the article (0.2% offset) 10 to 15 kg./mm. tensile strength 20 to treated to cool down to room temperature but in some 26 kg./mm. elongation (Delta 10) 20% to 12% d a instances it has been found desirable to interrupt the Brinell hardness of 50 to 60 kg./mm. When said artlficlal aglng treatment to Permit other Operations to alloys are artificially aged at elevated temperatures the he perfehhen before t final artificial aging takes P following average values are obtained for their mechanin the latter s n It has been found Preferable to 0011- cal properties: yield strength 18 to 28 kg./mm. tensile tlnne the PfehmlharY eltifieial aging until the article strength 28 to 32 kg./mm. elongation 14% t 10% d possesses a hardness which does not increase during the a Brinell hardness of 70 to 95 kg./mm. (measured with Perled thehftlete s e at room teInPelatnfe between 2.5 mm. ball with a load of 32.5 kg. for thirty seconds). r r y artlfielal aging treatment n the final It has been known for some time that when Al-Mg-Si al'tlfielal g treatmentalloys which are poor in copper are permitted to age at The follolfvlng example illustrates the advantages of room temperatures for substantial periods of time before the Process P accordance h t tion- A series artificial aging at elevated temperatures, the mechanical of test speclnlens of an alloy composed of properties achieved are not as good as when the arti- (179% 079% M -S e and th fi i l aging i commenced i di l fte the alloys 0 remamder Al were sub ected to a solution heat treatment h b h i property f the at 550: 5 C. for one hour. One series of the specialloys has lead to problems in their heat treatment, for s Was h quenched in Water at room temperature it is not always desirable or practical to subject the and 1mmed1ately l artificial aging in an a products to an artificial aging immediately after quench- Oven at Portlon for eight hours and the ing. For exam l if t samples of an ll composed other for fifteen hours. The other series of specimens f 002% c 079% M 079% 93% was sub ected t o-th e same solution heat treatment but Fe and its remainder A1 are subjected to a solution heat was q e 011 a temperature f 150 C. and treatment at 550 C. for about 1 hour and quenched in Placed thesame alf Ovens for aging as $0011 as y water at 20 C. and a portion of su h t t samp1es i reached equilibrium temperatures, one portion also was 1mmed1ately subjected to artificial aging in an air oven aged for eight hours and h r or 15 hours. The at 150 to 155 C. for eight hours and the other portion following chart indicates the differences in the mechanical is permitted to remain at room temperature for an hour properties obtained in the two series of tests. In the before being sub ected to the same artificial aging treatchart the designation NW indicates the series quenched ment the following properties are obtainedinthe samples: in water and the designation IW indicates the series quenched in oil. sti eii in s r ih Ek'mga' k rn rn.=' k jiu m pgi' dilt Yield Strength, g g hhgp gg, LengtholArtificlal kgJmm. percent I Artilgiclally a s immediately Aging ritn r ifi igati"sonata;- NW 1W NW 1W NW quenching 26. 4 33. 5 15. 8

shout-s 34. 25 35.7 37. 25 38.3 10

Room temperature storage before artificial aging has 15 mm 1 the same detrimental effect upon all alloys of the These values show the improvement obtained by the IX'OCBSS in accordance with the invention when compared vith normally used processes carried out under the most avorable conditions, which conditions, however, cannot I6 practically achieved in commercial scale operations.

A further series of tests were carried out with eight .pecimens of the same alloy which had been subjected o a solution heat treatment. In each series of the tests ll'le specimen was quenched in water at room temperaure and after an intervening period of exactly ten min ltes placed in an air oven and heated to 150 C. and .rtificially aged therein for fifteen hours and the other pecimen was quenched in oil at 150 C. and immedi- .tely placed in the air oven and aged for fifteen hours. lpecimens 1, 3, and 7 were those quenched in water ind specimens 2, 4, 6 and 8 were those quenched in oil.

It will be seen from a comparison of the latter chart Iith the former chart that the values obtained when there i a 10 minute delay between the quenching in Water and 1e artificial aging are only slightly different from the alues obtained when the specimen is immediately sub- :cted to age hardening after quenching in water. It may, owever, be clearly seen that the process in accordance Iith the invention produces a recognizable improvement 1 the properties of the alloy treated. The average values f the properties obtained for the tensile strength and ield strength with the process in accordance with the avention are not only considerably better but the variaions are in a considerably narrower range.

It is furthermore interesting that the progress of the ardening obtained with artificial aging in accordance r ith the present invention substantially parallel that obained when the alloys are quenched to room tempera- Jre and immediately artificially aged so that for given eriods of artificial aging substantially the same hardesses are obtained.

Corrosion tests have also shown that the corrosion esistance of alloys artificially aged in accordance with me invention is considerably greater than when prior art rocesses are employed. For example, corrosion tests Iere made with test specimens of an Al-Mg-Si alloy of 1c type specified, one series being quenched in water at com temperature and immediately artificially aged at 50 C. for various periods and the other series being uenched in oil at 150 C. and artificially aged by being iaintained at such temperature for varying periods of me.

The aging periods for each series were selected as our hours, eight hours, sixteen hours and seventy two ours.

The corrosion test consisted of immersing suitably preared specimens in an aqueous half normal NaCl soluon containing Vz% of concentrated HCl and measuring 1e amount of hydrogen evolved. After three hours ealtmgnt the following volumes of hydrogen were vo ve While the ab

Kết quả (Việt) 1:

Hoa Kỳ bằng sáng chế xử lý nhiệt của hợp kim nhôm Otto Schaaber, Schorndorf, Đức Al-Mg-Si loại miễn là họ không chứa một lượng đáng kể của đồng. Số lượng đồng đàn áp efiect bất lợi của nhiệt độ phòng lưu trữ khác nhau nhưng là một mức độ nhất định tỷ lệ thuận với số lượng 01 5 MgzSi hiện nay. Không có bản vẽ. Ứng dụng 6 tháng 5 năm 1949, nó là một đối tượng của phát minh này để cung cấp một giấy phép Serial số 91,861 tiểu thuyết fwtlkllichhwill pflocess gging nhân tạo ra một oys o e một ove gõ để pro uce pro ucts o o y 4 trai cải thiện tính chất cơ học.The present invention relates to a novel artificial age It is a further object to provide a novel process which hardening treatment for age hardenable aluminum alloys will increase the corrosion resistance to artificially aged which undergo spontaneous age hardening at room tem- -Mgy peratures to the detriment of subsequently performed Still another ob ect of the invention 1s to provide a artificial aging treatments. More particularly the invenpr e the heat treatment of alloys which tion relates to the treatment of aluminum alloys whose W111 Petmlt subsequent artificial g hardening to Produce principal alloying elements are magnesium and silicon in eXeellent mechanlcal properties even though such alloys approximately the stoichiometric proportion of MgzSi a stored at room temperature between the time y and wherein the proportion f Mggsi i between 05% are subjected to solution heat treatment and the artificial and 3.0% and containing no more than about 0.3% of aglng treatmentcopper and preferably not more than 0.1% of copper. It Was fohnd galloys even When quenched These Al-Mg-Si alloys may also contain silicon in excess from a solution heat treatment in water at 20 C. and. of the stoichiometric proportion MgzSi, manganese in e labesatory conditions, immediately subjected tn amounts up to 1.5% and not more than a total f 1.0% artificial aging at elevated temperatures do not achieve of other alloying element h as for l copper as favorable mechanical properties as those achieved by less than 0.3% preferably less than 0.1%, Zn less than h Process In accoi'danee With the inventiohp 0.5%, Cr less than 0.5% and Fe less than 0.5%. Alloys trons p eemmerelal scale it is not practically p of the following composition are especially suitable for slhle t0 subleet e alloys t0 artificial aging at elevated treatment in accordance with the invention; Mg 0.3% P as qnlekly as is Possible in Operations 011 a to 15% preferably 07% t 10%, Si 01% t 15% laboratory scale and usually at least above five minutes preferably 0.7% to 1.2%, Mn less than 1.5% preferably Intervene between t quenching and the artificial aging between 0.6% t 10% C l h 03% preferably l In accordance with the invention it has been discovered h 01%, Z l h 03%, C l h 03%, i that substantial advantages are obtained when Al-Mg-Sl' less than 0.5% and the remainder substantially aluminum. alloys a q e from a uti n heat treatment in a Alloys of thi ty are ll bj t d to a l quenching medlum which is maintained at the tempera- 'tion heat treatment at 520 to 570 C. and are then tine required for the artificial aging of the alloys namely quenched and subsequently aged either at room tembetween ahd p y between perature or artificially aged at temperatures between 120 a and are maintained at such temperature and 200 0. preferably 140 to 160 c. to improve their untll deslretl Properties of the alley are produced. mechanical properties. When such alloys are aged at The tlme Q WhlQh the alloy is maintained depends uP011 room temperatures the following average mechanical 40 h prepertles which are sought in the y- The artifiproperties are obtained in the alloys: yield strength elal aglng y be Completed Without Permitting the article (0.2% offset) 10 to 15 kg./mm. tensile strength 20 to treated to cool down to room temperature but in some 26 kg./mm. elongation (Delta 10) 20% to 12% d a instances it has been found desirable to interrupt the Brinell hardness of 50 to 60 kg./mm. When said artlficlal aglng treatment to Permit other Operations to alloys are artificially aged at elevated temperatures the he perfehhen before t final artificial aging takes P following average values are obtained for their mechanin the latter s n It has been found Preferable to 0011- cal properties: yield strength 18 to 28 kg./mm. tensile tlnne the PfehmlharY eltifieial aging until the article strength 28 to 32 kg./mm. elongation 14% t 10% d possesses a hardness which does not increase during the a Brinell hardness of 70 to 95 kg./mm. (measured with Perled thehftlete s e at room teInPelatnfe between 2.5 mm. ball with a load of 32.5 kg. for thirty seconds). r r y artlfielal aging treatment n the final It has been known for some time that when Al-Mg-Si al'tlfielal g treatmentalloys which are poor in copper are permitted to age at The follolfvlng example illustrates the advantages of room temperatures for substantial periods of time before the Process P accordance h t tion- A series artificial aging at elevated temperatures, the mechanical of test speclnlens of an alloy composed of properties achieved are not as good as when the arti- (179% 079% M -S e and th fi i l aging i commenced i di l fte the alloys 0 remamder Al were sub ected to a solution heat treatment h b h i property f the at 550: 5 C. for one hour. One series of the specialloys has lead to problems in their heat treatment, for s Was h quenched in Water at room temperature it is not always desirable or practical to subject the and 1mmed1ately l artificial aging in an a products to an artificial aging immediately after quench- Oven at Portlon for eight hours and the ing. For exam l if t samples of an ll composed other for fifteen hours. The other series of specimens f 002% c 079% M 079% 93% was sub ected t o-th e same solution heat treatment but Fe and its remainder A1 are subjected to a solution heat was q e 011 a temperature f 150 C. and treatment at 550 C. for about 1 hour and quenched in Placed thesame alf Ovens for aging as $0011 as y water at 20 C. and a portion of su h t t samp1es i reached equilibrium temperatures, one portion also was 1mmed1ately subjected to artificial aging in an air oven aged for eight hours and h r or 15 hours. The at 150 to 155 C. for eight hours and the other portion following chart indicates the differences in the mechanical is permitted to remain at room temperature for an hour properties obtained in the two series of tests. In the before being sub ected to the same artificial aging treatchart the designation NW indicates the series quenched ment the following properties are obtainedinthe samples: in water and the designation IW indicates the series quenched in oil. sti eii in s r ih Ek'mga' k rn rn.=' k jiu m pgi' dilt Yield Strength, g g hhgp gg, LengtholArtificlal kgJmm. percent I Artilgiclally a s immediately Aging ritn r ifi igati"sonata;- NW 1W NW 1W NW quenching 26. 4 33. 5 15. 8shout-s 34. 25 35.7 37. 25 38.3 10Room temperature storage before artificial aging has 15 mm 1 the same detrimental effect upon all alloys of the These values show the improvement obtained by the IX'OCBSS in accordance with the invention when compared vith normally used processes carried out under the most avorable conditions, which conditions, however, cannot I6 practically achieved in commercial scale operations.A further series of tests were carried out with eight .pecimens of the same alloy which had been subjected o a solution heat treatment. In each series of the tests ll'le specimen was quenched in water at room temperaure and after an intervening period of exactly ten min ltes placed in an air oven and heated to 150 C. and .rtificially aged therein for fifteen hours and the other pecimen was quenched in oil at 150 C. and immedi- .tely placed in the air oven and aged for fifteen hours. lpecimens 1, 3, and 7 were those quenched in water ind specimens 2, 4, 6 and 8 were those quenched in oil.It will be seen from a comparison of the latter chart Iith the former chart that the values obtained when there i a 10 minute delay between the quenching in Water and 1e artificial aging are only slightly different from the alues obtained when the specimen is immediately sub- :cted to age hardening after quenching in water. It may, owever, be clearly seen that the process in accordance Iith the invention produces a recognizable improvement 1 the properties of the alloy treated. The average values f the properties obtained for the tensile strength and ield strength with the process in accordance with the avention are not only considerably better but the variaions are in a considerably narrower range.It is furthermore interesting that the progress of the ardening obtained with artificial aging in accordance r ith the present invention substantially parallel that obained when the alloys are quenched to room tempera- Jre and immediately artificially aged so that for given eriods of artificial aging substantially the same hardesses are obtained.Corrosion tests have also shown that the corrosion esistance of alloys artificially aged in accordance with me invention is considerably greater than when prior art rocesses are employed. For example, corrosion tests Iere made with test specimens of an Al-Mg-Si alloy of 1c type specified, one series being quenched in water at com temperature and immediately artificially aged at 50 C. for various periods and the other series being uenched in oil at 150 C. and artificially aged by being iaintained at such temperature for varying periods of me.The aging periods for each series were selected as our hours, eight hours, sixteen hours and seventy two ours.The corrosion test consisted of immersing suitably preared specimens in an aqueous half normal NaCl soluon containing Vz% of concentrated HCl and measuring 1e amount of hydrogen evolved. After three hours ealtmgnt the following volumes of hydrogen were vo ve While the ab