GB2158459A - Solder - Google Patents

Abstract

A solder for joining copper pipes, for example by means of a capillary fitting, comprises tin with 0.3-0.7wt% copper.

Description

SPECIFICATION Improvements in or relating to joints This invention relates to solders and to soldered joints.

According to one aspect of the present invention we provide a solder comprising an alloy containing 0.3-0.7wt% copper, the balance apart from incidental elements and impurities being tin.

According to another aspect of the present invention we provide a method of forming a fluid-tight, soldered joint between a pair of tubular members of copper or a copper alloy wherein an end portion of one of the members is coaxially located within an end portion the other member with the overlapping end portions defining an annular space therebetween, and a quantity of molten solder is introduced into the space and is then solidified, characterised in that the solder comprises an alloy containing 0.3-0.7wt% copper, the balance apart from incidental elements and impurities being tin.

According to yet another aspect of the present invention we provide an integral solder ring capillary pipe fitting of copper or a copper alloy, characterised in that the solder comprises an alloy containing 0.3-0.7wt% copper, the balance apart from incidental elements and impurities being tin.

In each aspect of the invention, the solder alloy preferably contains about 0.5wt% copper.

The invention has especial application to the jointing of tubular members of copper, for example copper pipes of the type typically used in potable water or central heating plumbing systems. However, the invention is equally applicable to the jointing of members of other metals that generally can be jointed by tin-based solders, for example certain copper alloy members.

Preferably, and in accordance with BS219/1977, impurities should be kept within the following maximum levels: Bismuth 0.1 wt% Arsenic 0.03wt% Iron 0.02wt% Zinc 0.003wt% Aluminium 0.001wt% with the total of all other impurities not exceeding about 0.08wt%.

We have discovered that the solder of the invention can offer a high level of joint integrity and, in particular, is well suited to the manufacture of integral solder ring pipe fittings, such as those sold under our trade mark "YORKSHIRE", in which the or each integral solder ring is introduced into the fitting body (usually made of copper or copper alloy) by either a molten solder injection process or a "cold-fill" process. At the same time, the solders have the advantage that they need contain no lead (unlike the 60wt% tin/40wt% lead solders that are conventionally used in the jointing of copper pipes) and are therefore much more acceptable from the health and environmental point of view.

1. A solder comprising an alloy containing 0.3-0.7wt% copper, the balance apart from incidental elements and impurities being tin.

2. A solder according to Claim 1 wherein the alloy contains about 0.5wt% copper.

3. A method of forming a fluid-tight, soldered joint between a pair of tubular members of copper or a copper alloy wherein an end portion of one of the members is coaxially located within an end portion the other member with the overlapping end portions defining an annular space therebetween, and a quantity of molten solder is introduced into the space and is then solidified, characterised in that the solder comprises an alloy containing 0.3-0.7wt% copper, the balance apart from incidental elements and impurities being tin.

4. A method according to Claim 3, characterised in that the alloy contains about 0.5wt% copper.

5. An integral solder ring capillary pipe fitting of copper or a copper alloy, characterised in that the solder comprises an alloy containing 0.3-0.7wt% copper, the balance apart from incidental elements and impurities being tin.

6. A fitting according to Claim 5, characterised in that the alloy contains about 0.5wt% copper.

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

Claims (6)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Improvements in or relating to joints This invention relates to solders and to soldered joints. According to one aspect of the present invention we provide a solder comprising an alloy containing 0.3-0.7wt% copper, the balance apart from incidental elements and impurities being tin. According to another aspect of the present invention we provide a method of forming a fluid-tight, soldered joint between a pair of tubular members of copper or a copper alloy wherein an end portion of one of the members is coaxially located within an end portion the other member with the overlapping end portions defining an annular space therebetween, and a quantity of molten solder is introduced into the space and is then solidified, characterised in that the solder comprises an alloy containing 0.3-0.7wt% copper, the balance apart from incidental elements and impurities being tin. According to yet another aspect of the present invention we provide an integral solder ring capillary pipe fitting of copper or a copper alloy, characterised in that the solder comprises an alloy containing 0.3-0.7wt% copper, the balance apart from incidental elements and impurities being tin. In each aspect of the invention, the solder alloy preferably contains about 0.5wt% copper. The invention has especial application to the jointing of tubular members of copper, for example copper pipes of the type typically used in potable water or central heating plumbing systems. However, the invention is equally applicable to the jointing of members of other metals that generally can be jointed by tin-based solders, for example certain copper alloy members. Preferably, and in accordance with BS219/1977, impurities should be kept within the following maximum levels: Bismuth 0.1 wt% Arsenic 0.03wt% Iron 0.02wt% Zinc 0.003wt% Aluminium 0.001wt% with the total of all other impurities not exceeding about 0.08wt%. We have discovered that the solder of the invention can offer a high level of joint integrity and, in particular, is well suited to the manufacture of integral solder ring pipe fittings, such as those sold under our trade mark "YORKSHIRE", in which the or each integral solder ring is introduced into the fitting body (usually made of copper or copper alloy) by either a molten solder injection process or a "cold-fill" process. At the same time, the solders have the advantage that they need contain no lead (unlike the 60wt% tin/40wt% lead solders that are conventionally used in the jointing of copper pipes) and are therefore much more acceptable from the health and environmental point of view. CLAIMS

1. A solder comprising an alloy containing 0.3-0.7wt% copper, the balance apart from incidental elements and impurities being tin.

2. A solder according to Claim 1 wherein the alloy contains about 0.5wt% copper.

3. A method of forming a fluid-tight, soldered joint between a pair of tubular members of copper or a copper alloy wherein an end portion of one of the members is coaxially located within an end portion the other member with the overlapping end portions defining an annular space therebetween, and a quantity of molten solder is introduced into the space and is then solidified, characterised in that the solder comprises an alloy containing 0.3-0.7wt% copper, the balance apart from incidental elements and impurities being tin.

4. A method according to Claim 3, characterised in that the alloy contains about 0.5wt% copper.

5. An integral solder ring capillary pipe fitting of copper or a copper alloy, characterised in that the solder comprises an alloy containing 0.3-0.7wt% copper, the balance apart from incidental elements and impurities being tin.

6. A fitting according to Claim 5, characterised in that the alloy contains about 0.5wt% copper.