US2380838A - Magnesium base alloy - Google Patents

Description

m nses my 31, 1945 uNrri-zo STATES PA'TE MAGNESIUM Bass annoy i n. Hanawal Midlan to a corporation of No Drawing. Application November 10, 1e41, Serial No. 410,015

4 Claims. (CL 75-138) 'l'his invention relates to magnesium base alloys and more particularly concerns a magnesium base 11,10! having dairable physical properties such as -excellent iormabili 'qy. yield, and tensile strensths.

coupled with a high degree oi weldabllity.

Magnesium alloys are now extensively emliloyed in various structural'and mechanical arts where a light weight metal is highly advantaaoous.

the like. However, the useoi' magnesium alloys in rolled iormto make sheet metal articles requiring both forming and welding operations has not progressed as rapidly dueto the fact that heretofore alloys were not obtainable having a desirable combination properties, such as excellent i'ormability, tensile and yield strena hs,

and desirable welding characteristics.

'It is, accordingly, the principal object of this invention to provide a magnesium base alloy hav. ing excellent iormability, high yield and tensile strengths, and a high degree or weldability.

Other objects and advantages oi the invention will be apparent as the description proceeds.

My invention resides in the discovery that a magnesium base alloy composed of from 1 to 3 per cent of manganese and from 0.02 to 0.05 per cent of calcium. the balance being substantially all magnesium, possesses the aforementioned properties. The term magnesium" used herein and in the appended'claims is intendedto include magnesium containing the ordinary impurities 'i'oimd in, the commercially pure metal, such as traces oi. iron copper, nickel, and silicon. While the Prop rties of excellent strength, good tormability, and desirable welding characteristics are manifest over the entire range oi composition indicated, a preferred composition contains from 1.2 to 2 per cent manganese 0.04percentcalcium.

The-following tablelistssomeoithep per tiesoirolledaheetmadei'rommynewalloyand eoi'npares these properties with rolled sheet made and from 0.'03 to- 'iromrelatedalioys. Acolmarisonottheproperties showsthe improvement in strength char.-"

7 acterlstics; iormability', and weldability oi my new alloy over that or the closely related alloys. .In--

elonsationis'toberesarded asameasureoithe ductility or iormabilityoi the specimen. I

.such as for use in making castings, iorgings, and

The properties listed in the above table-under the section headed "Anneal were obtained by first rolling the alloys at a temperature of 500 to 700 1". and thereai'ter annealing them at a temperature oi. 800 to 700- 1". A comparison oi the properties listed in the table shows that the combined properties 01' the new alloy are greatly superior to those of the related alloys having similar percentages of alloyinl ingredients. Thus, itwillbenotedthatthenewalloycontaininghoth manganese and calcium showed a high degree oi improvement in its combined properties over that oi the binary magnesium-manganese alloy or the binary magnesium-calcium alloy.

Ithasbeenioundthatitisessentialtohave at least 0.02 per cent or calcium present in the "atthesamemthecompositionissuitableiori so use-whereweldsare tobemade.

alloy composition in order to obtain a high degree of elongation and thus excellent torniabiliw characteristics. At the same time; it hasbeen round that the per cento: calciumpresent in the alloying composition must not exceed about 0.05 orsheets made iron the alloy do'not possess good welding characteristics. For example, the calcium content or the alloy exceeds about 0.00 per cent, cracks develop in and about the weld bead rendering the weld imsatisi'actory. This cracking tendency is especially noticeable iitheweldisstressedtoanydegree. However. a composition containing betweenabout 0.02 and 0.06 per cent 0! calcium poueeses excellent tormabilitycharacterisflcsasshoar bythetablaand,

2 I emcee is,

otcoummoatuaemintherormoreheetl andthelikewhereinaweldingoperatlonlenecesearytooompletethetabrlcationoflheflniahed article such as in making airplane tank: from terials with magnesium, such as by adding the respective materials singly or- Jointly to a bath of molten magnesium which is Preferably protected from oxidation by a suitable flux.

I'clnim: 1. Abaa'oalloycontainingtrom 1.3 to 2 percent'ofmanganeoeandtrom 0.03 to0.04 .percent oi. cnlciunthebalancebeingmbstan- 'tiallyallmagneaium.

2. A magnesium base-alloy containing 1.5 per 'cent of manganese and 0.04 per cent of calcium. the remainder being substantially all magnesium. 3. AweldedarticlecontainingimmltoBper cent of manganese. 0.02 to 0.05 per cent 01 calcium, the remainder being-substantially all mag- A magnesium base alloy containing from 1 to 3 per cent 01 and from 0.02 to0.05

15 per cent-o1 calcium, the balance being substantially all magnesium.

v J D. HANAWALT.