ASTM B678-23
Standard Test Method for Solderability of Metallic-Coated Products

Standard No.

ASTM B678-23

Release Date

2024

Published By

American Society for Testing and Materials (ASTM)  US  /  ASTM

Status

Be replaced

Replace By

ASTM B678-25

Latest

ASTM B678-25

Introduction

Standard Core Content Interpretation

ASTM B678-23 specifies standardized test methods for evaluating the solderability of metallic coatings. This standard primarily applies to commonly solderable coatings such as tin, tin-lead alloys, silver, and gold. This standard utilizes a qualitative "pass-fail" decision mechanism and uses Sn60Pb40 or Sn63Pb37 solders with non-activated rosin flux.

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Comparative Analysis of Technical Parameters

Key Parameters	Standard Requirements	Common Deviations in Industry
Solder Temperature	245±5°C	230-260°C
Immersion Time	5±0.5sec	3-10sec
Flux Concentration	25±5% Rosin Solution	20-30%

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Key Steps in the Test Process

1. Specimen Preparation: Maintain original surface condition (unless otherwise specified)
2. Artificial Aging (if necessary): 100°C steam environment for 24 hours
3. Flux Application: Use Grade WW rosin solution
4. Solder Dipping: Strictly control immersion/withdrawal speed at 25±5mm/s
5. Result Judgment: A bright and smooth solder layer must be formed on more than 95% of the area

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Standard Application Case

A manufacturer of electronic connectors found that tin-plated products had poor soldering. The B678-23 standard test found that:

• The pass rate of samples without aging test was 100%
• The pass rate dropped to 65% after steam aging
• Root cause analysis revealed excessive porosity in the coating.

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Implementation Recommendations

Equipment Selection

Automated dip soldering equipment is recommended to avoid manual deviations. The solder tank capacity should meet the requirement of a 100:1 ratio of sample mass.

Abnormal Handling

When poor soldering occurs within 3mm of the edge, this area should be excluded from evaluation according to standard requirements. For large specimens (>25mm), a segmented testing method is recommended.

Quality Control

Establish a retention sample system, using critical qualified samples as physical standards for daily inspections. Replace the solder every 8 hours and record chemical analysis results.