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Cored Solder Wire Standards and Specification
Questions and Answers

Last Updated: 24 January 2020
Average Read Time: 3 to 5 minutes

What is J-STD-004?

J-STD-004 is the standard produced by the IPC to control and regulate the flux used in cored solder wire and solder paste. This is the industry standard used by all manufacturers in the UK and throughout Europe.

The latest version of this standard is J-STD-004B Amendment 1, published in 2011.

What is IPC-TM-650

This IPC method states how the test for halide content in a soldering flux.

In order to test the halide content of a solder wire, the wire is melted to expose the flux. The flux is then extracted into a solvent. Using this method, the inorganic halide generated is the same as during the soldering process. The quantity of this inorganic halide can then be determined using ion chromatography.

Have solder wire fluxes always been controlled by J-STD-004?

Before the introduction of the Joint Industry standards (J-STD-004) the classification of the flux within solder wire was controlled by BS 5625 and the reliability tests of the flux were controlled by some of the big manufacturers, which included British Telecom, The Ministry of Defence and the Canadian Telecoms manufacturer Bellcore.

There is also the ISO 9454-1:2016 standard of flux specifications. However, as most clients use the J-STD-001, the J-STD-004B is more relevant at this time.

Do the specifications of the J-STD-004 ever change?

Standards, as technology progresses, do change to meet the ever-demanding needs of electronic assembly industries, as the technologies of the solder wire manufacturers develop different techniques and chemicals to create solder wire products.

What are the changes?

Changes are due to the detection of the halide and the activity of flux within the wire. As manufacturers formulations advanced, the detection methods were no longer sufficient to keep pace with the technology changes.

Changes have been made to the specification to ensure that customers are truly aware of what they are using to assemble their products, as well as those of their customers.

The chemistry involved in the activity systems becomes increasingly more complex. For example, in many versions of fluxes the manufacturers have switched to halogen activation. Halogen activated fluxes do not turn into halides until the point of use when heat is applied, which means that the halides are hidden when the correct procedures are not followed.

What did the changes detect?

1995: J-STD-004 first introduced

Halide products were classified by the Silver Chromate Test, which is a wet chemical test.

As the technologies advanced in the halide compounds, the halides were not always recorded at their true levels. It was also possible to use non-ionic halogen activators which are not detected by this simple test.

2004: J-STD-004A

The Amendment introduced an optional Ion Chromatography Test, or the use of the traditional silver chromate test for halides.

With the introduction of Ion Chromatography, the halides that previously did not show themselves with the wet chemical tests, were detected. Halogens which were present as non-ionic compounds were still not detected.

2008: J-STD-004B

Introduction of mandatory Ion Chromatography test for halides.

Ionic halides present in the flux prior to soldering are now fully detected by the Ion Chromatography Test. However, the test does not detect the halogens that are present as non-ionic compounds, which decompose during the soldering process to form ionic halides.

2011: J-STD-004B Amendment 1

The IPC method now dictates that the flux extraction for testing halides requires heat to extract the flux from the wire. Using this method, the halogen containing activator decomposes to generate an inorganic halide, which occurs during the soldering process, and this can be determined.

Halogen activated wires are now one the biggest areas of concern, because if the product datasheet does not declare the testing method as IPC-TM-650, then the halogen will not be detected and therefore does not comply to the latest standard.

Flux J-STD-004
J-STD-004B Amendment 1
Nexus Nu-Clear ROL0 ROL0 ROL1* ROM1*
Nexus Gold ROL0 ROL0 ROL1* ROL1
Nexus Space ROL0 ROL0 ROL0 ROL0
Autosol RA ROL1 ROL1 ROM1* ROM1
Envirosol ROL1 ROL1 ROL1 ROL1
* denotes a change in classification based on an amendment to the standard

Warton Metals provides a full range of flux cored solder products to suit all applications. For more information on our range of flux cored solder wires please visit our cored solder wire page.

View our range of flux cored solder wires

What is the makeup of a no clean cored solder wire flux?

What is a halide?

A halide is an ionic halogen formed using any of the Section 17 elements from the periodic table. These are fluoride, chloride, bromide and iodide - hence the 'ides' in halide. With the activity of the halide decreasing as we move down the table.

Halides improve soldering performance because they increase the cleaning power of the organic acid and the speed of soldering. The lower the halide percentage the more reliable the joint. However, it is slower to solder.

Should I be concerned about halide in my solder wire?

The problem with halides is that they are relatively simple ionic compounds that can start to reactivate under the presence of moisture, resulting in corrosion and electromigration. In a cored solder wire the halide is encapsulated within the rosin (or resin), which reduces the effect of humidity.

Too much halide can impact the reliability of manufactured products over a period of time, and under certain environmental conditions.

Should I avoid halides and only use halide free products?

Halides do not need to be avoided, as they are safe to use but should only be used when they are tested in accordance with the latest version of J-STD-004B (Amendment 1) and their use is applicable to your J-STD-001 procedure or customer specification.

Why are halides used at all in cored solder wires?

The reason that halides are still used in cored solder wires is that they are effective on a variety of components and board finishes, with a wide process window.

Users require a fast formed and mechanically reliable solder joint which at the same time must meet the appropriate environmental stability of the residues post-soldering. This can be achieved by using the ionic halide activators. The design rules are well known and available in industrial standards. For example, J STD-001 and customer specifications.

How to choose which no clean solder wire?

The halide content may be specified by a customer, who might require a halide free wire, which would be a ROL0. Alternatively, they may specify a small amount of halide (up to 0.5%) which would be a ROL1, or else a faster flowing solder, which would mean a higher halide amount (between 0.5% - 2%), in which case it would be a ROM1.

Your customer will be expecting you to make products on their behalf using best manufacturing standards such as J-STD-001 or J-STD-001 (Space Amendment where the use of ROM1 solder is specifically prohibited for certain operations).

J-STD-001 refers to J-STD-004 (Requirements for Soldering Fluxes).