GB2132534A - Backing bars for use in welding processes - Google Patents

Abstract

A backing bar for a welding process comprises an elongate bar 1 formed in its uppermost surface with a shallow channel 2 whose base is substantially flat. The bar includes at least two rows of passageways 5 set substantially normal to the flat surface of the shallow channel and positioned to place the channel in communication with a source of protective gas, e.g. argon. The bar may be of steel, copper or aluminium. The passageways 5 of one row may be offset with respect to those of the neighbouring row. The ends of the passageways 5 remote from the shallow channel 2 may communicate with a gas-in-feed channel 6. <IMAGE>

Description

SPECIFICATION Backing bars for use in welding processes This invention relates to backing bars for use in welding processes in which a protective gas atmosphere is employed.

Backing bars are used to confine weld beads as they are laid down to define a seam between adjoining metal pieces. Conventionally such bars comprise a metal bar of sufficient length to span the seam to be welded and include a 'V' shaped or arcuate groove into which a protective gas e.g.

argon is admitted through a row of spaced passageways which place the groove in connection with a source of the gas. Hitherto the holes have been drilled with bores inclined to the vertical.

Previous backing bars have the disadvantages that they are expensive to produce and that the weld surface is often found to be irregular or uneven because the gas is not evenly distributed throughout the seam length.

According to the present invention a backing bar for a welding or like process comprises an elongate bar formed in its uppermost surface with a shallow channel whose base is substantially flat, the backing bar including at least two rows of passageways set substantially normal to the flat surface of the groove and positioned to place the channel in connection with a source of protective gas. The bar may be manufactured from a suitable metal, for example steel, copper or aluminum.

Preferably the passageways of each row are offset with respect to the adjoining passageways of the neighbouring row to ensure a more even gas distribution along the entire length of the channel. The passageway ends remote from the channel are preferably countersunk and communicate with a second channel formed in the under surface of the bar which is adapted to convey gas from the gas source to the individual passageways.

The protective gas may be argon.

The invention will now be described with reference to accompanying diagrammatic drawings in which: Figure 1 is a plan view from above of a backing bar in accordance with the invention; Figure 2 is a plan view from below the bar illustrated in Figure 1: Figure 3 is an end view taken in the direction of arrow A shown in Figure 1; Figure 4 is a section taken along line lV-lV of Figure 1; and Figure 5 shows an enlarged detail of Figure 4.

The backing bar illustrated comprises an elongate metal bar 1 of steel, copper or aluminum which is formed in its upper surface with an elongate shallow channel 2 of a length at least equal to the length of seam to be welded. As will be seen from Figures 3 and 4 the channel 2 has a flat base 3 and sides 4 which extend normal to the base.

Two sets of passageways 5 place a channel 2 in communication with a further channel 6 formed in the undersurface of the backing bar and adapted to be connected to a source of protecting gas under pressure (not shown). The passageways 5 are set substantially normal to the flat base 3 and are countersunk at their lower extremities 7. The passageways of one row are offset with respect to the passageways of the other row.

When in use, location of the backing bar below the seam to be welded between two metal pieces is assisted by means of holes 8 drilled through one or each end of the backing bar. Protective gas e.g. argon is supplied via the lower channel 6 and the passageways 5 to the shallow upper channel 2 to provide in addition to a protective atmosphere for the weld bead a gas support cushion for the weld metal whilst molten and a cooling medium which rapidly chills the weld bead.

It has been found that the use of backing bars such as described leads to the production of weld beads having flat even profiles which require no further dressing even when used in an external surface of a welded assembly.

The backing bar can be used in conjunction with any welding processes where a protective gas atmosphere is employed.

Claims (Filed on 21/Nov/83) 1. A backing bar for a welding or like process comprising an eiongate bar formed in its uppermost surface with a shallow channel whose base is substantially flat, the backing bar including at least two rows of passageways set substantially normal to the flat surface of the shallow channel and positioned to place the channel in communication with a source of protective gas.

2. A backing bar as claimed in Claim 1 wherein the bar is manufactured from Steel, copper or Aluminium.

3. A backing bar as claimed in Claim 1 or Claim 2 wherein the passageways of each row are offset with respect to the adjoining passageways of the neighbouring row to ensure a more even gas distribution along the entire length of the channel.

4. A backing bar as claimed in any one of the preceeding claims wherein the ends of the passageways remote from the channel communicate with a second channel formed in the under surface of the bar, which second channel is adapted to convey gas from the gas source to and through individual passageways to the shallow channel formed in the uppermost surface of the bar.

5. A backing bar as claimed in any one of the preceeding claims wherein the gas is argon.

6. A backing bar for a welding or like process substantially as herein described with reference to Figures 1 to 5 of the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (6)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Backing bars for use in welding processes This invention relates to backing bars for use in welding processes in which a protective gas atmosphere is employed. Backing bars are used to confine weld beads as they are laid down to define a seam between adjoining metal pieces. Conventionally such bars comprise a metal bar of sufficient length to span the seam to be welded and include a 'V' shaped or arcuate groove into which a protective gas e.g. argon is admitted through a row of spaced passageways which place the groove in connection with a source of the gas. Hitherto the holes have been drilled with bores inclined to the vertical. Previous backing bars have the disadvantages that they are expensive to produce and that the weld surface is often found to be irregular or uneven because the gas is not evenly distributed throughout the seam length. According to the present invention a backing bar for a welding or like process comprises an elongate bar formed in its uppermost surface with a shallow channel whose base is substantially flat, the backing bar including at least two rows of passageways set substantially normal to the flat surface of the groove and positioned to place the channel in connection with a source of protective gas. The bar may be manufactured from a suitable metal, for example steel, copper or aluminum. Preferably the passageways of each row are offset with respect to the adjoining passageways of the neighbouring row to ensure a more even gas distribution along the entire length of the channel. The passageway ends remote from the channel are preferably countersunk and communicate with a second channel formed in the under surface of the bar which is adapted to convey gas from the gas source to the individual passageways. The protective gas may be argon. The invention will now be described with reference to accompanying diagrammatic drawings in which: Figure 1 is a plan view from above of a backing bar in accordance with the invention; Figure 2 is a plan view from below the bar illustrated in Figure 1: Figure 3 is an end view taken in the direction of arrow A shown in Figure 1; Figure 4 is a section taken along line lV-lV of Figure 1; and Figure 5 shows an enlarged detail of Figure 4. The backing bar illustrated comprises an elongate metal bar 1 of steel, copper or aluminum which is formed in its upper surface with an elongate shallow channel 2 of a length at least equal to the length of seam to be welded. As will be seen from Figures 3 and 4 the channel 2 has a flat base 3 and sides 4 which extend normal to the base. Two sets of passageways 5 place a channel 2 in communication with a further channel 6 formed in the undersurface of the backing bar and adapted to be connected to a source of protecting gas under pressure (not shown). The passageways 5 are set substantially normal to the flat base 3 and are countersunk at their lower extremities 7. The passageways of one row are offset with respect to the passageways of the other row. When in use, location of the backing bar below the seam to be welded between two metal pieces is assisted by means of holes 8 drilled through one or each end of the backing bar. Protective gas e.g. argon is supplied via the lower channel 6 and the passageways 5 to the shallow upper channel 2 to provide in addition to a protective atmosphere for the weld bead a gas support cushion for the weld metal whilst molten and a cooling medium which rapidly chills the weld bead. It has been found that the use of backing bars such as described leads to the production of weld beads having flat even profiles which require no further dressing even when used in an external surface of a welded assembly. The backing bar can be used in conjunction with any welding processes where a protective gas atmosphere is employed. Claims (Filed on 21/Nov/83)

1. A backing bar for a welding or like process comprising an eiongate bar formed in its uppermost surface with a shallow channel whose base is substantially flat, the backing bar including at least two rows of passageways set substantially normal to the flat surface of the shallow channel and positioned to place the channel in communication with a source of protective gas.

2. A backing bar as claimed in Claim 1 wherein the bar is manufactured from Steel, copper or Aluminium.

3. A backing bar as claimed in Claim 1 or Claim 2 wherein the passageways of each row are offset with respect to the adjoining passageways of the neighbouring row to ensure a more even gas distribution along the entire length of the channel.

4. A backing bar as claimed in any one of the preceeding claims wherein the ends of the passageways remote from the channel communicate with a second channel formed in the under surface of the bar, which second channel is adapted to convey gas from the gas source to and through individual passageways to the shallow channel formed in the uppermost surface of the bar.

5. A backing bar as claimed in any one of the preceeding claims wherein the gas is argon.

6. A backing bar for a welding or like process substantially as herein described with reference to Figures 1 to 5 of the accompanying drawings.