US3656918A - Composite welded ferrous article - Google Patents

Abstract

A low carbon steel weld deposit containing chromium up to 1.0, preferably 0.05-0.6, per cent. by weight, nickel 6.5-11, preferably 7-9, per cent. by weight, molybdenum up to 1.0, preferably 0.2-0.8, per cent. by weight and vanadium up to .12, preferably 0.04-0.09, per cent. by weight. Also a low carbon steel weld deposit consisting essentially of Per Cent. by Weight Element BroadPreferred Carbon 0.030.120.06-0.10Manganese 0.05-1.00.1-0.8Silicon 0.200.700.25-0.55Chromium up to 1.00.05-0.6Nickel 6.5-1179Molybdenum up to 1.00.2-0.8Vanadium up to 0.120.040.09Phosphorus 0.020 max.0.012 max. Sulfur 0.020 max.0.012 max. Iron BalanceBalance WHICH EXHIBITS A YIELD STRENGTH OF AT LEAST 130 KSI AND Charpy V-notch energy absorption at -60* F. of at least 20 ft.-lbs. after heat treatment consisting of austenitizing at 1,500* F. for 1 hour, water quenching, tempering at 1,100* F. for 1 hour and water quenching.

Description

[54] COMPOSITE WELDEID F ERROUS ARTICLE [72] Inventors: William T. De Long; Paul T. Corcoran, both of West Manchester Township, York County, Pa.

[73] Assignee: Teledyne, Inc., Los Angeles, Calif. [22] Filed: Dec. 30,1969

[2]] Appl. No.: 889,321

I52] U.S. Cl ..29/l96.l [51 I Int. Cl ..B32b 15/00 [58] Field of Search ..29/196.l; 75/123 K, 128 [56] References Cited UNITED STATES PATENTS 2,516,125 7/1950 Kramer ..75/123 K 2,992,148 7/1961 Yeo ..75/123 K 3,290,128 12/1960 Manganello ..75/128 V Primary Examiner--Hyland Bizot Attorney-Edward l-loopes, III

[57] ABSTRACT A low carbon steel weld deposit containing chromium up to 1.0, preferably 0.05-0.6, per cent. by weight, nickel 6.5-11,

[151 3 656 91 [451 Apr. 1, 1972 preferably 7-9, per cent. by weight, molybdenum up to 1.0, preferably 0.2-0.8, per cent. by weight and vanadium up to .12, preferably 0.04-0.09, per cent. by weight.

Also a low carbon steel weld deposit consisting essentially of Percent by WeLuhl which exhibits a yield strength of at least 130 ksi and Charpy V-notch energy absorption at 60F. of at least 20 ft.-lbs. after heat treatment consisting of austenitizing at l.500 F.

for 1 hour, water quenching, tempering at 1,100 F. for 1 hour and Water quenching.

1 Claim, No Drawings The invention herein described was made in the course of or under a contract or subcontract thereunder with the Department ofthe Navy.

This invention relates to steel weld deposits; more particularly, it relates to low alloy steel weld deposits which exhibit high strength and notch-toughness both as-welded and after heat treatment.

In the field of low alloy high strength steels with yield strengths above about 100 ksi, particularly HY-l30/ 150 type steels with yield strengths of at least 130 ksi, there has been a need for high performance weld metals which in asingle deposit will have yield and tensile strengths and impact toughness approximately equal to those of the base metal both as-deposited and in the heat treated (i.e., quenched and tempered) condition. Weld deposited metal is always under a handicap compared with plate material and must be more shrewdly formulated because it lacks the advantages of the mechanical hot work treatments which produce grain refinement in plate material. In spite of this handicap low alloy steel weld deposit analyses and methods of deposition have been developed which produce as-deposited metal with yield strength at least matching that of the available hot worked and heat treated plate material, coupled with suitable toughness. Requiring the highest quality welding processes, such deposits were recently produced by means of inert gas shielded methods used with high purity alloy-bearing filler wires. This level of performance has first been achieved with deposits from manual low hydrogen lime-fluoride covered electrodes, which was a more difficult goal. However, heat treatment of such deposits, often necessary in the fabrication of heavy sections, causes a drop in mechanical properties, often to levels which are unacceptable in the end use of the weldment.

We are able to produce steel weld deposits which exhibit yield strengths above 100 ksi and typically 130-160 ksi and Charpy V-notch toughness above 20 ft.-lbs. at -60 F. and typically 30-50 ft.-lbs. at 60 F both as-deposited according to recommended procedures, and after a heat treatment typically consisting of austenitizing at l,500 F. for 1 hour, water quenching, tempering at 1,l F. for 1 hour and again water quenching. As compared to earlier weld metals of the HY-l30/I50 type, which are suitable for as-welded use but not for heat treatment, our weld deposits are characterized by a novel balance of those chemical elements which have proven most effective in the as-welded grades, and also by a retention of the earlier emphasis on limitations in the harmful elements phosphorus and sulfur to levels below 0.020 per cent. by weight and preferably below 0.012 per cent. by weight.

A particularly attractive aspect of our weld deposits is that they may exhibit the above mentioned as-deposited and heattreated properties when deposited with low hydrogen limefluoride covered electrodes utilizing conventional commercial quality rimmed steel core wires. Such electrodes, which were the chosen means for producing weld deposits which established the existence and limitations of our invention, offer significant economic advantages over the simpler but much more expensive high purity wire and gas-metal-arc (GMA) processes which are also applicable and which have heretofore been widely used in investigating and producing HY-l 30/150 weld metals.

We provide low carbon steel weld deposits characterized by chromium up to 1.0 per cent. by weight, nickel 6.5 11 per cent. by weight, molybdenum up to 1.0 per cent. by weight and vanadium up to 0.12 per cent. by weight; the deposits preferably contain chromium 0.05 0.6 per cent. by weight, nickel 7 9 per cent. by weight, molybdenum 0.2 0.8 per cent. by weight and vanadium 0.04 0.09 per cent. by weight.

We further provide a weld deposit consisting essentially of Percent by Weight Chromium up to 1.0 Nickel 6.5-1 1 Molybdenum up to 1.0 Vanadium .up to 0.12 Phosphorus 0.020 max. Sulfur 0.020 max. Iron Balance In a preferred form the deposit consists essentially of Percent by Weight We further provide such deposits that exhibit yield strengths of at least ksi and Charpy V-notch energy absorption at 60 F. of at least 20 ft.-lbs. after heat treatment consisting of austenitizing at 1,500 F. for 1 hour, water quenching, tempering at 1,100 F. for 1 hour and water quenching.

Realization of the optimum as-welded properties of our improved weld deposits will depend on the conditions under which they are deposited, as will be appreciated by those skilled in the art. In the I-IY-130/ area certain practices, such as low welding heat input and small bead size, are known to maximize as-welded strength and toughness of the deposit; somewhat surprisingly, however, the as-welded properties of our deposits are relatively insensitive to heat input, which is a significant advantage when they are produced with covered electrodes under field conditions. In addition to such general practices the specific welding process employed to produce our improved weld deposits will have a definite effect on the degree of retention of the maximum as-welded deposit properties attainable; it is well established that the higher the weld metal purity, the more its properties will approach the optimum for its overall alloy balance. Purity in this context not only means low levels of residual or tramp elements such as phosphorus, sulfur, nitrogen and oxygen but also includes aspects such as size and shape of inclusions, etc. The gas-tungsten-arc (GTA) process with pre-alloyed high purity filler metal additions, which provides the highest purity weld metal, can be expected to be optimum for producing our deposits; somewhat lower on the scale, although still very good, is the GMA process utilizing argon-oxygen or equivalent shielding gases and pre-alloyed electrode wire. As above indicated, we have also found that our new analysis can be weld deposited with good results close to those obtained with the GMA process and at much lower cost with properly formulated high quality low hydrogen lime-fluoride covered electrodes. Deposits produced by other types of covered electrodes or submerged arc welding can be expected to exhibit inferior aswelded properties to a degree dependent on the specific process used and the purity of the resultant weld metal. Heattreated properties are less dependent on welding processes and conditions since austenitizing of the deposit causes recrystallization, which wipes out many of the effects of welding variables.

The low hydrogen lime-fluoride covered electrode which we have used for producing our deposits meets a general specification for this class of electrode and consists of a mild steel core and a lime-fluoride coating thereon, the electrode containing by weight about 45 per cent. to about 80 per cent. core and about 20 per cent. to about 5 5 per cent. coating, the coating containing by weight of the electrode up to about 30 per cent. iron powder and alloying metal powder, about 2 per cent. to about 7 per cent. deoxidizer metal powder, about 4 per cent. to about 15 per cent. metal fluoride, about 5 per cent. to about 15 per cent. alkaline earth carbonate, 0 to about 10 per cent. slag builder and modifier and about 0.5 per cent. to about 8 per cent. inorganic binder material. Although We hav Ch n to pply a y ay of the Coating fOr Table 2) with low hydrogen lime-fluoride covered electrodes.

reasons ofeconomy in our electrode, it is ofcourse possible to In preparing the deposits, only one welder and one power introduce all or part of the alloy through the core Wire. source were used, and all test weldments were made in the flat Other details, objec s an advant ges of th inv n i n will position using reverse polarity direct current. Multipass welds become apparent as the following description of certain 5 were prepared using stringer beads and a temper bead deposipreSent Preferred embodiments h r ofpro tion sequence. Welding parameters were controlled so that a calculated heat input of 30 i 2 kilojoules per inch would be maintained. Each pass in a test weldment was completed with TABLE 1 one electrode only and no starts or stops were located in the Welding conditions used in preparing weld deposits test area. Preheat and interpass temperatures of the test weld- C a d D ment were maintained at 250 25 F. in an attempt to Plate material: 2 pieces of one-inch-thick U.S. Steel preclude any hydrogen-ceased Cracks in the po a o HY130(T) plate, minimum di i 10" l X minimum interpass delay time was used. Table 2 lists chemical 4 wide compositions and mechanical test results obtained with the Chemistrv; 012 C, 090 Mn, 034% Si, four deposits A B, C and D after heat treatment in land 4- 0 97 Cr, 49 Niy 050% MO 064% V, inch-thick sections. Heat treatment consisted of austenitizing 0.002% P, 0.008% S at l,500 F. for 1 hour, water quenching, tempering at l,l00

F. for l hour and water quenching again; this cycle was simu- Jomt: Type single V lated for the 4-inch thickness by blower cooling i-inch-thick PreparationFla.me cutting followed by grinding 1 2 3 on each plate sections from the austenitizing and the tempering tempera- El t d tures. it will be seen that our deposits are not strongly affected by changes in manganese or nickel content within the above defined preferred limits; compare deposits A and B for examle. De osits A and B also illustrate that our preferred Backup plat? .steel H T .Onemcbthmk eposits show excellent heat-treated properties in section plate one Inch mmlmum m Wldth X 1011 length thicknesses as high as 4 inches. Chromium higher than our Welding position: Flat preferred limits but within our broad limits, as illustrated by Welding current: 18515 amps DC, reverse polarit deposits C and D, appears to lower the heat-treated yield strength in thick sections; for best performance we prefer chromium on the order of 0.5 per cent. Deposits C and D also Heat put: 30:1: 2 k l j u s P inch illustrate the beneficial effect of small vanadium additions to Preheat and interpass temperature; 250 F 25 our deposits. The two deposits are essentially equivalent except for vanadium content, and while both show decreases in heat-treated yield strength in thick sections because of Wire! Type-00nventi0nal commercial-quality chromium contents somewhat higher than optimum, it will be rlmmed steel seen that the vanadium addition provides a significant in- Chemistr v0.07% C, 0.50% Mn, 0.005% Si crease in yield strength while causing only a relatively small 0.007 P, 0.020 S loss in impact properties in view ofthe gain in yield strength.

CoatingLoW hydrogen lime-fluoride type Welding voltage: 24 volts Interpass delay: 1 hour minimum TABLE 3 Effect of heat input on as-welded properties Deposit E analysis: .085% C, .52% Mn, .51% Si, 43% Cr, 8.29% Ni, .49% M0, .065% V Yield Elon- Reduc- Heat strength gation tion Charpy V-notch energy input, (0.2% Tensile in of absorption, it.-lb. kilojoules ofiset), strength, 2 inches, area, Deposit per inch K s.i. K s.i. percent percent 80 F. 0 F. F. 30. 6 155 165 16. 4 59. 9 47. 8 44. 8 42. 3 59. 3 145 167. 5 15. 7 54. 8 46. 8 42. 5 38. 3

TABLE 2 Compositions and properties of heat treated weld deposits Yield Elon- Plate strength gation Charpy V-notch energy thick- (0.2% in 1.4 Red. of absorption. tt.-lb. ncss, oflset), Tensile inches, area, Deposit C Mn Si Cr Ni Mo V inches k s. strength percent percent F. 0 F. 60 F 1 149 158 19. 3 61. 3 51. 5 51. 8 47 52 i 37 1611).? 7. 0 5s. 5 53. s to. s 48.8 5 9. 3 64. 7 51. 6 51 47. 6 .31 .48 7. 93 .45 .077 ,1, i 3 7 8 48. 5 41 3 5 48. 5 61 47. 5 .30 .95 8.82 .46 .076 ,1, 9 8 2 5M 62 3 48 8 5 5. 66. 5 66. 6 64. 5 67 Table 1 lists welding conditions used in preparing four of To illustrate the insensitivity of as-welded properties of our our improved weld deposits designated A, B, C and D (see deposits to heat input, Table 3 compares data on two deposits,

E and F, prepared with 5/32-inch-diameter low-hydrogen lime-fluoride covered electrodes under conditions similar to those shown in Table l, at respective heat inputs of 30.6 kilojoules per inch, generally considered desirably low, and

Heat-treated properties of our deposits are dependent on the specific heat treatment employed. We prefer to employ a standard heat treatment consisting of austenitizing at 1,500 F. for 1 hour, water quenching, tempering at l,l F. for one 59.3 kilojoules per inch, which is rather high for /32-inch 5 hour and water quenching again. In general an increase in electrodes of the high strength type. The deposit chemical tempering temperature will cause a decrease in yield and tenanalyses were virtually identical; that for deposit E is shown at sile strength and a increase in Charpy V-notch impact strength the top of the table. Although a slight drop in yield strength in the heat-treated deposit.

occurred with the higher heat input, the lower yield strength While We have described Certain present preferred embodiwas still well above the 130 ksi minimum required of deposits ments of the invention it is to be distinctly understood that the of this type; tensile strength and Charpy energy absorption invention is not limited thereto but may be otherwise variously were only slightly affected by the higher heat input. embodied within the scppe of the following claims.

TABLE 4 Compositions and properties or as-welded and heat-treated deposits Charpy V-noteh energy Yield Elonstrength gation absorption, it.-1b. Electrode (0.2% in 1.4 Red. diameter, Condloffset), Tensile inches, 01 area, Deposit inches C Mn Si Cr Ni Mo V tion" K s. strength percent percent 80 F. 0 F. 60 F m {as l 153 iii? 33:? 22:? ii? iii? E: es: .085 .52 .51 .43 8.29 749 .065 2 AW=As-Welded; HT=Heat-Treated.

Table 4 lists compositions, as-welded properties and heat- We claim: treated properties in l-inch thick specimens of two of our im- 1. A composite comprising a base consisting essentially of proved deposits prepared with low hydrogen lime-fluoride by weight covered electrodes of one-eighth inch and five thirty-seconds carbon m imum inch diameters respectively under conditions similar to those 30 gfigjg-gg shown in Table 1. Deposit E is the same deposit E shown in chromium 036474 Table 3. It will be seen from Table 4 that'both as-welded and nickel 4.68-5.32 heat-treated our improved weld deposits exhibit excellent 5:22:33 83:31"? strength and toughness for both electrode sizes tested. g

Graphical and statistical study of the data generated in se- 3 5 ries of experiments from which the data of Tables 2, 3 and 4 were obtained produced the above described limits of analyses of our improved weld deposits.

Although the deposits described in Tables 2, 3 and 4 were produced with low hydrogen lime-fluoride covered electrodes, similar results have been achieved with deposits produced by the gas-metal arc (GMA) process; typical GMA welding involves a .062- diameter bare wire electrode, 320 amperes and 26 volts direct current reverse polarity and 98 per cent. argon, 2 per cent. oxygen shielding gas at 50 cubic feet per hour flow rate. Similarly, our improved weld deposits may be produced by other welding processes such as gas-tungsten-arc welding, submerged arc welding, electroslag welding, etc. Any such process should be suitable as long as the weld deposit conforms to the above described composition.

having thereon a weld deposit consisting essentially of which weld deposit in the heat treated condition austenitizing at 1,500 ing at l,1()0 F. for 1 produced by F. for 1 hour, water quenching, temperhour and water quenching exhibits a yield strength of at least ksi and Charpy V-notch energy absorption at -60 F. of at least 20 ft.-lbs.

UNITED STATES PATENT o ETEE @ERTIFECATE 0F CQRREQTWN Patent No. 3 656,918 Dated April 18, 1972 Inventor(s) William T. DeLong and Paul T. Corcoran It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

' In the table in the ABSTRACT, opposite "Chromium" under "Broad", "up to 1.10" should read --up to l..O-.

Column 3, line 21, "22 8" should be --22-l/2--; column 5, in Table 4 after "G and "E" under "Deposit", cancel the equal signs; line 43, ".062 diameter" should be -.,062" diameter-; column 6, in Table 4, opposite "6 under "80 F.", "53.2" should be --53.5..

Signed and sealed this 15th day of August 1972.

USCOMM-DC 60376-P69 US. GOVERNMENT PRINT\NG OFFICE: i969 0-365-334 (SEAL) s r T Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSGHALK Attesting; Officer Commissioner of Patents