ASTM B774/B774M-21

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it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: B774 − 00 (Reapproved 2014) B774/B774M − 21
Standard Specification for
Low Melting Point Alloys and Solders
This standard is issued under the fixed designation B774;B774/B774M; the number immediately following the designation indicates the
year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last
reapproval. A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope Scope*
1.1 This specification covers low-melting point metal alloys and solders, including bismuth-tin, bismuth-lead, bismuth-tin-lead,
bismuth-tin-lead-cadmium, bismuth-tin-lead-indium-cadmium, bismuth-tin-lead-indium, indium-lead, and indium-lead-silver, and
indium-tin joining together two or more metals at temperatures below their melting points; blocking for support and removable
borders; radiation shielding; fusible plugs; fuses; tube bending; and punch setting.
1.1.1 This specification shall include those alloys having a liquidus temperature not exceeding 361°F (183°C),361 °F [183 °C], the
melting point of the tin lead eutectic.
1.1.2 This specification includes low-melting point alloys in the form of solid bars, ingots, powder and special forms, and in the
form of solid ribbon and wire.
1.2 The values stated in either inch-pound units or SI units are to be regarded as standard. The values given in parentheses are
mathematical conversions to SI units that are provided for information only and are not considered separately as standard. Within
the text, SI units are shown in brackets. The values stated in each system may not be exact equivalents; therefore, each system shall
be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to become familiar with all hazards including those identified in the appropriate Material Safety Data
Sheet (MSDS) for this product/material as provided by the manufacturer, to establish appropriate safety safety, health, and
healthenvironmental practices, and determine the applicability of regulatory limitations prior to use.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
E55 Practice for Sampling Wrought Nonferrous Metals and Alloys for Determination of Chemical Composition
E88 Practice for Sampling Nonferrous Metals and Alloys in Cast Form for Determination of Chemical Composition
2.2 Military Standard:
MIL-STD 129 Marking for Shipment and Storage
This specification is under the jurisdiction of ASTM Committee B02 on Nonferrous Metals and Alloys and is the direct responsibility of Subcommittee B02.02 on Refined
Lead, Tin, Antimony, and Their Alloys.
Current edition approved Oct. 1, 2014April 1, 2021. Published October 2014May 2021. Originally approved in 1987. Last previous edition approved in 20102014 as
B774B774 – 00 (2014). – 00 (2010). DOI: 10.1520/B0774-00R14.10.1520/B0774_B0774M-21.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Available from Standardization Documents Order Desk, DODSSP, Bldg. 4, Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098, http://dodssp.daps.dla.mil.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
B774/B774M − 21
2.3 Federal Standard:
Fed. Std. No. 123 Marking for Shipment (Civil Agencies)
3. Terminology
3.1 Definitions:
3.1.1 producer, n—the primary manufacturer of the material.
3.1.2 supplier, n—the seller of the material to the purchaser (may or may not be the producer).
3.2 Definitions of Terms Specific to This Standard:
3.2.1 liquidus, n—the lowest temperature at which an alloy is fully transformed from a solid to a liquid.
3.2.2 lot, n—the term “lot” as used in this specification shall be defined as follows: for solid alloy metal, a lot shall consist of all
the metal of the same time designation, produced from the same batch of raw materials under essentially the same conditions, and
offered for inspection at one time.
3.2.3 lot number, n—the term “lot number” as used in this specification refers to a numerical designation for a lot that is traceable
to a date of manufacture.
3.2.4 solidus, n—the highest temperature at which an alloy is fully transformed from a liquid to a solid.
4. Classification
4.1 Type Designation—The type designation shall use the following symbols to properly identify the material:
4.1.1 Alloy Composition—The composition is identified by three numbers that relate to the melting point in degrees Fahrenheit
where it is eutectic or six numbers where it is a range alloy.
4.1.2 Form—The form is indicated by a single letter in accordance with Table 1.
4.1.3 Powder Mesh Size—The powder mesh size is identified by a size symbol number (Table 2).
5. Ordering Information
5.1 Orders for material under this specification shall indicate the following information, as required, to adequately describe the
desired material:
5.1.1 Type designation (see 4.1),
5.1.2 Detailed requirements for special forms,
5.1.3 Dimensions of ribbon and wire solder (see 9.2),
5.1.4 Unit weight,
5.1.5 Packaging (see Section 18),
TABLE 1 Form
Symbol Form
B bar
I ingot
P powder
R ribbon
S special (includes pellets, preforms, shot, etc.
S special (includes pellets, preforms, shot, etc.)
W wire
B774/B774M − 21
TABLE 2 Powder Mesh Size
Size Symbol Powder Mesh Size
3 325
2 200
1 100
5.1.6 Marking (see Section 17),
5.1.7 ASTM specification designation and year of issue, marked on the purchase order and on the package or spool, and
5.1.8 Special requirements, as agreed upon between supplier and purchaser.
6. Materials and Manufacture
6.1 The producer shall use care to have each lot of alloy as uniform in quality as practicable and of satisfactory appearance in
accordance with the best industrial practices. Each bar, ingot, or other form in which the alloy is sold shall be uniform in
composition within the entire lot.
7. Chemical Composition
7.1 The composition of the alloys covered by this specification shall be as shown in Table 3.
NOTE 1—By mutual agreement between the supplier and the purchaser, analysis may be required and limits established for elements or compounds not
specified in Table 3.
8. Physical and Performance Requirements
8.1 Alloy must freeze within 2°F 2 °F [1.1 °C] of its solidus.
8.2 Powder Mesh Size—The powder mesh size shall be as specified in 5.1.1 and 4.1.3.
9. Dimensions and Unit Weight
9.1 Bar and Ingot—The dimensions and unit weight of bar and ingot shall be agreed between the supplier and purchaser.
TABLE 3 Chemical Requirements Composition, wt. %
(range or maximum rules)
Alloy Constituents — wt % Melting Points
Designation Solidus Liquidus
Bi Pb Sn Cd In Ag Cu Sb Zn °F °C °F °C
117 44.2–45.2 22.1–23.1 7.8–8.8 4.8–5.8 18.6–19.6 0.001 0.08 0.1 0.08 117 47 117 47
129–133 48.14–50.14 16.92–18.92 10.55–12.55 129 54 133 56
136 48.5–49.5 17.5–18.5 11.5–12.5 0.005 20.5–21.5 0.001 0.08 0.1 0.08 136 58 136 58
158 49.5–50.5 26.2–27.2 12.8–13.8 9.5–10.5 0.008 0.001 0.08 0.1 0.08 158 70 158 70
158–165 49.5–50.5 24.45–25.45 12.0–13.0 12.0–13.0 0.10 158 70 165 74
158–190 42.0–43.0 37.2–38.2 10.8–11.8 8.0–9.0 0.008 0.001 0.08 0.1 0.08 158 70 190 88
174 56.5–57.5 0.05 16.5–17.5 0.005 25.5–26.5 0.001 0.08 0.1 0.08 174 79 174 79
203 52.0–53.0 31.5–32.5 15.0–16.0 0.005 0.008 0.001 0.08 0.1 0.08 203 95 203 95
203–239 49.5–50.5 24.5–25.5 24.5–25.5 203 95 239 115
216–217 53.5–54.5 25.5–26.5 19.5–20.5 216 102 217 103
255 55.0–56.0 44.0–45.0 0.01 0.005 0.008 0.001 0.08 0.1 0.08 255 124 255 124
281 57.5–58.5 0.05 41.5–42.5 0.005 0.008 0.01 0.08 0.1 0.08 281 138 281 138
281–338 39.5–40.5 0.05 59.5–60.5 0.005 0.008 0.01 0.08 0.1 0.08 281 138 338 170
291–325 13.5–14.5 42.5–43.5 42.5–43.5 0.005 0.008 0.01 0.08 0.1 0.08 291 144 325 163
244 0.01 0.05 47.5–48.5 0.005 51.5–52.5 0.01 0.08 0.1 0.08 244 118 244 118
296 0.01 0.05 0.01 0.005 96.5–97.5 2.8–3.2 0.08 0.1 0.08 296 147 296 147
293 0.01 29.9–31.1 50.7–51.7 17.7–18.7 0.008 0.01 0.08 0.1 0.08 293 145 293 145
300–302 0.01 14.5–15.5 0.01 0.005 79.5–80.5 4.5–5.5 0.08 0.1 0.08 300 149 302 150
307–323 0.01 17.5–18.5 69.5–70.5 0.005 11.5–12.5 0.01 0.08 0.1 0.08 307 153 323 162
320–345 0.01 29.5–30.5 0.01 0.005 69.5–70.5 0.01 0.08 0.1 0.08 320 160 345 174
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9.2 Wire (Solid)—The dimensions and unit weight of wire alloys shall be as specified in 5.1.3 and 5.1.4. The tolerance on the
specified outside diameter shall be 65 % or 60.002 in. (0.05 mm),[0.05 mm], whichever is greater.
9.3 Other Forms:
9.3.1 Dimensions for ribbon and special forms shall be as agreed between the supplier and p
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