US3040846A - Built-up hollow field-weldable structural steel length - Google Patents

Description

June 26, 1962 N. R. ABBERLY BUILT-UP HOLLOW FIELD-WELDABLE STRUCTURAL STEEL LENGTH Filed Sept. 12, 1960 INVENTDR United States Patent G 3,040,846 BUILT-UP HOLLOW FIELD-WELDABLE STRUCTURAL STEEL LENGTH Nicholas Rippen Abberly, 4018 Worth St., Dallas 10, Tex. Filed Sept. 12, 1960, Ser. No. 55,501 8 Claims. (Cl. 189-24) This invention relates to steel lengths that contributorily constitute all types and sizes of structures, both earthanchored and movable, particularly the skeletons of tier structures, as well as relating to lengths that do not form a part of an inclusive structure, namely, poles. Excepting where qualified, the comprehensive expression, general lengths, including therefore poles as well, has been adopted herein.

The application of the invention is limited to lengths designed for aifixment in the field by welding; field welding is of course not associable with full heat-treatment, for which a furnace large enough to house the inclusive structure is used.

A salient ultimate aim consists in providing general lengths, respecting every contemplated ratio of length to weight or transverse dimensions, or of Weight thereto, with a structure-derived degree of strength that exceeds that attained in all comparable other general lengths. The expression, structure-derived, refers to the fact that, so far as concerns invention aspects, the augmentation in strength derives from geometric and afiixing and not from metallurgic innovations.

The salient possibilitating aim consists in providing, as part of each general length, an outside member or members, termed, shielding, constituted of relatively soft metal and which is at least limitedly field-weldable, and an inside member or members, termed, coring, of relatively hard metal, there being between the shielding and the coring, airspaces designed to obstruct the passage of outside welding heat from the shielding to the coring in an amount sufiicient to damage the latter.

The term, coring, a coined one, designates, in a given said length, the single core or plurality of core elements. A coring is simple when, transversely regarded, there is a single core element. It is complex when, transversely regarded, it consists of a plurality of core elements. Such a plurality is not to be confused with a longitudinally disposed plurality of simple cores. The herein adopted symbols for them, derived from said expressions, are SC and CC.

The shielding is preferably of machinable metal in the sense that holes can be drilled in it in the field with port able tools mounting cobalt drills and not necessarily carbide drills (because of the ditficulty of establishing a rigid relationship between the tool and the drilled object), altho carbide-tipped drills should be alternatively employable (instead of the cobalt drills). The expression, fieldweldable, will be defined elsewhere herein.

Admissible in all embodiments is every conceivable ratio between the long dimensions of the shielding and the coring. Coring constitutes, in every embodiment, at least an auxiliary strength member. Shielding, at one extreme, serves as a substantially nonstrength member with the sole function for it that of an afiixing means, and, at the other extreme, constitutes the main strength member, the one or more longitudinally distributed elongated but abbreviated cores supplying extra strength at critical points, otherwise expressed, locally. One embodiment of this last mentioned arrangement would be in a pole where the shielding constitutes the major strength member or main pole body. In such a pole, the coring consists of one or more abbreviated cores, with at least one of them stiffening the pole at the most highly stressed point, the anchoring zone. Like the traditional inside connectors of the liner 3,040,846 Patented June 26, 1962 type, one or more cores can so serve at the junctures between successive sections of poles too high to be integral.

To describe the invention in a few Words, the inventionincorporating structural hollow built-up steel length includes at least one first length-long integral member. It may be either an outside or an inside one. Additionally included is a least one elongated integral other member, which too may be an inside or an outside one, depending on which the first member is, and it too may be a length long one or an abbreviated one. The outside member is of a relatively soft steel and is transversely tensionally stressed in its coring girthing state. The shielding girths the coring in such a relation thereto that they adjoin one another transversely discontinuously. By this is meant there is a plurality of transversely successive mutually sep arated airspaces and, alternating with them, a plurality of transversely successive mutually separated pairs of contact-zone portions, the two in each pair being integral respective portions of the coring and the shielding. In each contact zone, the two in each pair pressurally engage one another at their mutually faying surfaces with the maximally extensive areas possible in order to minimize the ratio of unit pressure value to unit area value, so that shielding and coring of extreme contrast between their respective hardnesses can, if desired, be incorporated into the length. Generally, the shielding will be also more machinable and more field-weldable than the coring. Said air spaces serve to bar the transmission of most of the welding heat (which is applied in the field to the shielding) to the coring. What welding heat does reach the coring is of an amount insufficient to deleteriously alter the grain structure of and thereby weaken or embrittle the coring. The described relation facilitates the fabrication of steel lengths that, notwithstanding field-weldability, particularly when both the shielding and the coring are length-long, are stronger than any comparable, equally field-weldable steel lengths ever made, by virtue of the fact that the major strength member, the coring, can be constituted of a steel of such hardness that its incorporation into structures could not have been at all realistically contemplated before the advent of this invention.

Since ultimate tensile strength in steels is closely related to hardness, and, in the case of those heat-treated, almost perfectly, hardness numbers are used for comparing strengths. Detailed treatment of this matter is presented elsewhere.

Research in ferrous metallurgy will, perhaps soon, record advances leading to lifting present standards to still higher levels. An already solidly established boron-andless-than-one-percent-nickel limitedly field-weldable steel is available with 120 kips ultimate and kips yield strength. The qualification refers to the fact that the field-weldability can be had only with plural beads. Preheating and postheating, being only moderately beneficial, are not needed. To predict the appearance of a singlepass-field-weldable, less-than-one-percent-nickel, morethan-IZO-IOO-kips steel with no augmented cost for the other alloys, calls perhaps for a great measure of optimism. A conservative guess pictures, in the shielding, said IZO-IOO-kips steel improved to the point of being singlepass-field-weldable, and, in the coring, any suitable one of a number of already available, altogether nonfield weldable, extremely hard steels of the kind never incorporated into construction. Pending the appearance of said improved steel, the rule is laid down that, in all invention-incorporating lengths, the coring steel ultimate strength exceeds that of the shileding by at least '50 kips. This would seem to be reasonable in the light of the state of the art at the time this invention was conceived and this patent applied for. It is based on the use of said l20-l00-k-ips steel (unimproved) in the coring, and of 3 the ASTM A7 steel, with its 70 kips ultimate strength, in the shielding.

Because the hardness numbers in the carbide-ball Brinell system correspond, within three and mostly within two and many by less than one percent, to kips values doubled, they have been selected for indirectly designating shielding and coring ultimate strengths. In all invention-incorporating lengths the Brinell carbide-ball hardness number of the coring steel exceeds that of the shielding steel by 100.

The term, shopwelded, refers only to shopwelded coring elements, the welding being followed by full heattreatment in a completely enclosing furnace. The shopwelding of shielding, if any, is not accorded mention; it is not essentially related to the invention. Of the conceivable species two have been chosen for illustration and description herein. In the first the coring is simple. In the second it is complex. In both the cross-sectional form is circular. Either species is associable with a pole of constant diameter, with one that is straighttapered, and with one that is stepped-tapered, these three forms being of course not species-defining factors. In the accompanying drawing, to which now refer for a complete understanding of the invention, the two species are shown in association with only the two tapered forms.

FIGURE 1 is an elevation view of a straight-tapered pole of either the first or the second species.

FIGURE 2 is an elevation view of a stepped-tapered pole of either the first or the second species.

FIGURE 3 is a one-fourth symmetrical cross-sectional view in the plane 3-3 in FIGURE 1 and in the plane 3-3 in FIGURE 2, assuming that the two are of the first species.

FIGURE 4 is a one-fourth symmetrical cross-sectional view in the plane (4-4) in FIGURE 1 and in the plane (44) in FIGURE 2, assuming that the two are poles of the second species.

FIGURE 5 is a fragmentary elevation view of a fragment circumscribed at 5 in FIGURE 1 and of a fragment circumscribed at 5 in FIGURE 2, assuming that the two are poles of the second species.

In FIGURE 1, the pole body rests on the base, 11, and, at the top, bears the cap 12.

In FIGURE 2, the pole body rests on the base 13, and, at the top, bears the cap 14.

In FIGURE 3 can be seen the internally helically ribbed, relatively soft, field-weldable shielding, 15, and the externally helically threaded or ribbed, relatively hard, simple coring (core element), 16, which jointly constitute the greater part of the pole body in either FIGURE 1 or FIGURE 2 when it is one of the first species.

In FIGURE 4 can be seen the internally helically ribbed, relatively soft, field-weldable shielding, 17, and the relatively hard, complex coring 18-19, which consists of the core element 18 and the core element 19. These three elements jointly constitute the greater part of the pole body in either FIGURE 1 or FIGURE 2 when it is one of the second species.

Plain-surface core element 18 interveningly adjoins shielding 17 and the externally helically ribbed core element 19.

In the first species the helical direction of the shielding is opposite to that of the coring. In the second species the helical direction of the shielding is recommendedly opposite to that of the ribbed core element. Because of the mutual opposition of the helical directions, the direct mutual engagement of shielding ribs and coring ribs in the first species (and the indirect mutual engagement or radially projected intersection of the helical directions in the second species) is at points. These points coact to produce a faired state of the shielding (and of the coring) surface. Should the ribs in one element be parallel with those in the other, the pressure exerted on one another would tend to produce unsightly and also functionally undesirable ridges and hollows.

To fabricate and assemble the poles, plates that have been hot rolled with lengthwise extending ribs would be sheared on the bias in a manner whereby the rib direction is obliquely angular to the plate edges, for example, at an angle of forty-five degrees. Each now obliquely ribbed plate is buttwelded to constitute a tubular member. In the case of a tapered pole of the straight type a recommended procedure consists in heating the shielding to a plastic-working temperature, and the coring made a tapering one at either ambient temperature or 1 freezing temperature while the shielding is initially a constant-diameter tube. The two are very quickly forced into intercngagement, during which there is effected not only strength integration of the two members but the coring, functioning like a die imposes its own tapering form on the shielding. In the case of complex coring the two core elements are handled as if one was a coring and the other a shielding, whereupon the subassembly of the two is handled like a simple coring and assembled with the shielding in the manner described.

The pole body in FIGURE 2 can be an integral one but the stepped-tapered form actually is conditioned by the sectionalizing of the pole because of being too long for shipping as an integral pole. The connector at the base and those at the two junctures are represented by dotted lines.

llclaim:

1. A structural length consisting in the main of these components: an elongated tubular coring of relatively hard metal; a thereto interference-fitted, elongated, tubular shielding of relaively soft metal and girthing at least a part of the coring and having, on the inner surface thereof, a plurality of mutually parallel and helically disposed shielding ridges which are in pressural engagement with the coring, there being constituted, between the shielding and the coring, a plurality of airspaces.

2. A structural length as described in claim 1, said coring consisting of a single core element having, on the outer surface thereof, a plurality of mutually parallel and helically disposed coring ridges in pressural engagement with the therewith intersecting shielding ridges, the helical directions of the two said pluralities of ridges being opposite one another.

3. A structural length as described in claim 1, said coring consisting of two core elements, one being a tubular, innermost first core element having, on the outer surface thereof, a plurality of mutually parallel and helically disposed coring ridges, the other being a tubular, intervening second core element having a smooth inner and a smooth outer surface respectively pressurally engaging said coring ridges and said shielding ridges.

4. A structural length as described in claim 1, said coring consisting of two core elements, one being a tubular, innermost first core element having, on the outer surface thereof, a plurality of mutually parallel and helically disposed coring ridges, the other being a tubular, intervening, second core element having a smooth inner and a smooth outer surface respectively pressurally engaging said coring ridges and said shielding ridges, the helical directions of the two said pluralities of ridges being opposite one another.

5. A structural length as described in claim 1, the Brinell carbide-ball hardness number for the coring exceeding that for the shielding by at least one hundred.

6. A structural length as described in claim 1, said coring consisting of a single core element having, on the outer surface thereof, a plurality of mutually parallel and helically disposed coring ridges in pressural engagement with the therewith intersecting shielding ridges, the helical directions of the. twosaid pluralities of ridges being opposite one another, the Brinell carbide-ball hardness number for said core element exceeding that for the shielding by at least one hundred.

7. A structural length as described in claim 1, said coring consisting of two core elements, one a tubular innermost first core element having, on the outer surface thereof, a plurality of mutually parallel and helioally disposed coring ridges, the other a tubular intervening second core element having a smooth inner and a smooth outer surface respectively pressurally engaging said coring ridges and said shielding ridges, the Brinell carbide-ball hardness number for at least one of the two core elements exceeding that for the shielding by at least one hundred.

8. A structural length as described in claim 1, said coring consisting of two core elements, one a tubular innermost first core element having, on the outer surface thereof, a plurality of mutually parallel and helically disposed coring ridges, the other a tubular intervening second core element having a smooth inner and a smooth outer surface respectively pressurally engaging said coring ridges and said shielding ridges, the helical direotions of the two said pluralities of ridges being opposite one another, the Brinell carbide-ball hardness number for at least one of the two core elements exceeding that for the shielding by at least one hundred.

References Cited in the file of this patent UNITED STATES PATENTS 426,561 Dithridge Apr. 29, 1890 514,665 Serrell Feb. 13, 1894 1,179,696 Canada Apr. 18, 1916 2,960,114- Hinde Nov. 15, 1960

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