Патент USA US2127245код для вставки
Patented Aug. ‘16, 1938 v ‘ 2,127,245 UNITED STATES PATENT OFFICE 2,127,205 ALLOY Walter R‘. Breeler, Troy, N. Y., aslignor to Lud lum Steel 00., Watervliet, N. Y, a corporation of New Jersey No Drawing. ' Application July 19, 1935, Serial No. 32,237 6 Claims. (Cl. 75-124) My invention relates to alloy steels and particularly to steels having high resistance to hot oxldation, scaling, and corrosive .loss by the attack of compounds containing lead at high tem.1 peratures. The alloy is particularly adapted for - use in lead pots, pyrometer tubes and the like, and for exhaust valves, seat inserts and other parts of internal combustion engines which are subjected to contact with hot exhaust gases re- 10 sulting from the combustion of gasoline contalning lead anti-knock compounds. The alloys at present employed for these purposes are rather high priced, and one of the objects of my in vention is to produce a relatively cheap material characterized by its resistance to hot oxidation 20 as will be apparent from the following com parative tests of two alloys both of which con tain chromium and manganese in about the same amounts but in one of which the aluminum content is 3.1% with a silicon content of 0.6%. and in the other alloy no aluminum is present. but the silicon content is 2.8%. ' ' Lossinweight(mg./sq.em.lmin.) 0 Si 7. Cr Ai Mu Roch shorter, , 0,3 well 25 21 15s0° Nil Nil ‘800 as 20.4 20.8 limits between which they are employed are as follows: Neither 01' these alloys shows any loss in weight when subjected to lead oxy bromide at 1350° F. ‘ 0 _________________________________ __ At 1580° F. the alloy without the aluminum shows a rather substantial loss while the other shows Percent .05 to 3 8.9 1350'a 0-9 0.0 3.1 an who £38, 2Pbspi and to hot lead compounds. _ v The essential ingredients of my alloy and the _ us 0.6 , ' Mn __________ __'_____' _____________ __ 2.00 to 20 none. At 1800° F. the alloy without the aluminum Cr. more than _________________ __l___ 5.00 to 35 but with fairly high silicon when subjected to Al _______________________________ __ 35 Fe _______________________________ __ .50 to 15 26, to 92 A preferred range of the. above alloying ele ments is as follows: 80 C " 252mg’? M'g'i": """"""""""""" " 8'01; 0 12'o Cr_'_' :_:': """""""""""""" '" 18'0 to 22"} """ " 1:5 to 3:5 35 ' While the foregoing are the only elements necessary to attain the objects of my invention, other elements, in quantities which do not ap- preciably affect the basic characteristics of the alloy, namely, resistance to hot oxidation and to lead compounds at high temperatures, may be incorporated if desired. Such elements as selenium, tellurium, phosphorus and sulphur, in quantities up to 0.30% will improve the machineability of the alloy, and nitrogen in quan- lead oxide shows a loss exceeding three times that of the other, and at the same temperature with a mixture of lead oxide and lead sulphate the loss 0! the composition without the aluminum is about seventy times greater than the other. In ‘the preferred analysis range mentioned, 3 and in the lower ranges of aluminum, chro mium and manganese (especially aluminum), the alloy is readily iorgeable and rollable. In the higher ranges of alloy content (especially alumi nuin) the alloy is more diiilcult to hot ‘work 03 and requires more care at this operation. How ever, in cases where not working is impractical, the alloy may be readily east and used in this form My alloy can be made by any of the well known method-S 01' melting,- F0r- 6x81111116. when 1181118 an electric arc furnace the aluminum may be added as metallic aluminum or aluminum alloy 1n the furnace itself. 0!‘ the aluminum 01‘ 811 4 GI titles up to 0.3% will increase ‘the strength at heat and also the hardness. aluminum alloy maybeadded in the ladle. These additions are preferably made under protective Silicon, of course“ is always present in steels and irons, and. while’ I prefer‘ to keep the silicon under about 1%, the quantity in any case should slag coatings of such 8 nature that they will not react detrimentally with the aluminum steel and they should be of such composition as to dissolve 50 be less than the aluminum content. I ?nd that silicon in excess of the aluminum very greatly reduces the resistance of the alloy to corrosive or ?ux any undesirable oxides such as A1203. Instead of theelectric arc furnace, induction furnaces may be used. Such equipment may or loss when subjected to attack by lead contain' ing compounds at high temperature. Silicon and 15 valuminum are not interchangeable in the alloy may not be used with controlled, atmospheres. What I claim is: ~ 1. A readily rorgeable alloy steel containing a 2 2,197,245 plurality of elements and characterized by its manganese 8% to 12%, chromium 18% to 22%, and aluminum from 1.5% m 3.5%, with the bal resistance to hot oxidation and corrosive loss when subjectedv to attack by lead containing com pounds at temperatures ‘of the order of the ‘oper ating temperatures of exhaust valves in internal combustion engines; the only essentialelements necessary to obtain such characteristics being ance substantially all iron; the aluminum content being in ‘excess of the-silicon content, if any, in jsaid steel. carbon from 0.2% to 1%, manganese from 8% to 12%, chromium from 18% to 22%, aluminum from 1.5% to 3.5% with the balance substantially - . a ' 4. A readily forgeable alloy steel containing a plurality of elements and characterized by its high resistance to hot oxidation and corrosive lossrwhen subjected to attack by lead contain ing compounds at temperatures of the order of 10 “ all iron; the aluminum content being in excess‘ the operating temperatures of exhaust valves in of the silicon‘content. it any, in said steel. _ vinternal combustion engines; the only essential 2. An internal combustion engine valve char-v acterized by its high resistance to hot oxidation and corrosive loss when subjected to attack by 15 lead containing compounds at temperatures of the order of the operating temperatures of- ex haust valves in internal combustion engines; said valve comprising an alloy steel containing a plu rality of'elements of which the only essential elements necessary to obtain the foregoing char acteristics are carbon from 0.05% to 3%, man ganese from 2% to 20%,‘ chromium vfrom more than 5% to 35% and aluminum from 0.5% to 15%, with the balance substantially all iron; the aluminum content being in excess of the silicon content, it any, in said steel. 1 - . elements-necessary to obtain such characteristics being carbon from 0.2% to 1%, manganese from 8% to 12%, chromium from 18%, to 22%, and 15 aluminum from 1.5% to 3.5% with' the balance substantially all iron; the silicon content beingv less than 1% and less than the aluminum content. 5. An internal combustion engine valve com- ' prising the alloy of claim 4. v _ r 20 . ' 6. An internal combustion engine valve char acterized by its high resistance to hot voxidation and corrosive loss ‘when subjected to“ attack by lead containing compounds at temperatures of the order of the operating temperatures of- ex‘ haust valves in internal combustion engines; said -» valve comprising an alloy steel containing a plu rality of elements of which the only essential - 3. An internal combustion engine v'alve char acterized by its high resistance to hot oxidation elements necessary to obtain the foregoing char and corrosive loss when subjected to attack by acteristics are carbon from 0.05% to 3%, man lead containing compounds at temperatures of ganese from ‘2% to 20%, chromium ‘from more than 5% to 35% and aluminum from 0.5% to the order of the operating temperatures of ex haust valves in internal combustion engines; said 15%, with the balance substantially all iron; the valve comprising a readily forgeable alloy steel *' silicon content being less than 1%, and less than 35 containing a plurality of, elements of which the the aluminum content. only essential elements necessary to‘ obtain the - foregoing characteristics are carbon 0.2% to 1%, WALTER R. BREELER.