ASTM C1147-14(2022)

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.
Designation: C1147 − 14 (Reapproved 2022)
Standard Practice for
Determining the Short Term Tensile Weld Strength of
Chemical-Resistant Thermoplastics
This standard is issued under the fixed designation C1147; 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 mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
1.1 This practice covers the preparation and evaluation of
joints between two pieces of weldable grades of thermoplastic
2. Referenced Documents
materials, backed and unbacked, (such as those shown in Table
2.1 ASTM Standards:
1) up to 2 in. (50 mm) in thickness.
D883 Terminology Relating to Plastics
1.2 Since there are numerous new technologies and tech-
D4285 Test Method for Indicating Oil or Water in Com-
niques constantly being developed for plastic welding, there
pressed Air
are no profiles and procedures that can be considered as
D5947 Test Methods for Physical Dimensions of Solid
standard for all plastics at various thicknesses. This practice is
Plastics Specimens
not intended to define profiles and procedures; however, it is
E4 Practices for Force Calibration and Verification of Test-
intended to establish methods to evaluate minimum short term
ing Machines
weld factors to be achieved by the welder for the respective
plastics.
3. Terminology
1.3 Weld procedures used for test pieces shall reflect pro-
3.1 Definitions—For definitions of terms used in this
cedures to be used in actual fabrication.
practice, see Terminology D883.
1.4 Welding methods to be used include machine welding,
3.2 Definitions of Terms Specific to This Standard:
extrusion welding, and hot gas welding.
3.2.1 butt welding (machine)—the fusing together of two
1.5 This practice can be utilized by relevant certification
pieces of plastic which are aligned in the same plane, with the
bodies to assess welder proficiency and qualification.
same mating thickness, by application of heat and pressure,
also called hot-plate welding.
1.6 The values stated in inch-pound units are to be regarded
as standard. The values given in parentheses are mathematical
3.2.2 chemical-resistant—the ability of a material to resist
conversions to SI units that are provided for information only degradation by reaction with, dissolution by, or reduction of
and are not considered standard. physical continuity from contact with a chemical agent or
agents, thereby retaining its capacity to perform as a structural
1.7 This standard does not purport to address all of the
or aesthetic entity.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- 3.2.3 extrusion welding—a process in which heated plastic
priate safety, health, and environmental practices and deter- is forced through a shaping orifice (or die) and applied with
mine the applicability of regulatory limitations prior to use. pressure to suitably prepared, locally preheated plastic pieces
of the same resin base, to join them.
NOTE 1—There is no known ISO equivalent to this standard.
3.2.4 hot-gas welding—a technique for joining thermoplas-
1.8 This international standard was developed in accor-
tics (usually sheets) in which the materials are first softened by
dance with internationally recognized principles on standard-
a jet of hot gas from a welding gun. A rod of the same plastic
ization established in the Decision on Principles for the
isusedtofilltheheatedgapandjointhesheetsatthesametime
Development of International Standards, Guides and Recom-
pressure is applied by either the rod or the tip of the gun.
Sometimes referred to as string bead welding.
This practice is under the jurisdiction ofASTM Committee D20 on Plastics and
is the direct responsibility of Subcommittee D20.19 on Film, Sheeting, and Molded
Products. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Nov. 1, 2022. Published November 2022. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1990. Last previous edition approved in 2014 as C1147 – 14. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/C1147-14R22. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C1147 − 14 (2022)
TABLE 1 Typical Guide for Hot Gas Welding Temperatures
6. Apparatus
NOTE 1—For other welding techniques, consult material and equipment
6.1 Theapparatusforweldingshallconsistofthefollowing:
supplier for recommendations.
6.1.1 Welding Device, suitable for joining thermoplastics.
A
°F (°C) Recommended Gas
6.1.2 Air Supply, when needed, conforming to Test Method
B
Type
D4285.
HDPE 500–600 (260–316) Nitrogen or Air
PP 550–600 (288–316) Nitrogen or Air 6.1.3 Temperature Measuring Device, capable of measuring
PVC 500–550 (260–288) Air
the welding temperature to within 61 % for the specific plastic
CPVC 550–660 (288–349) Air
as set forth in Table 1.
PVDF 650–680 (343–360) Nitrogen or Air
ECTFE 665–695 (352–368) Nitrogen 6.1.4 Clamps, suitable for holding the specimen while
ETFE 675–710 (357–377) Air
welding.
FEP 650–725 (343–385) Air
6.1.5 Saw, suitable for cutting thermoplastic sheet.
PFA 675–750 (357–399) Air
MFA 536–554 (280–290) Air 6.1.6 Sander, Router, Joiner, or Saw, suitable for beveling
A
edges of sheet.
Measured ⁄4 in. (6 mm) inside weld tip, directly in gas stream.
B
Inert gas may be used in place of air.
6.2 Theapparatusfortestingtensionspecimensshallconsist
of the following:
6.2.1 Tensile Machine—A testing machine capable of pull-
3.2.5 hot-plate welding—synonymous with butt welding ing the specimens at a rate of 2 6 0.1 in./min (50 6 2.5
mm/min) of crosshead movement (speed of movement when
(machine).
the machine is running without a load).
3.2.6 short term weld factor—a dimensionless number that
6.2.1.1 The rate of movement between heads of the testing
provides a relative measure of the tensile strength of a welded
machineshallremainessentiallyconstantunderchangingloads
thermoplastic test specimen to the tensile strength of the
(see Note 2).
manufactured sheet.
NOTE 2—It is difficult to meet this requirement when loads are
4. Summary of Practice
measured with a spring type or pendulum type weighing device.
4.1 The sheets are prepared and welded. Tensile test speci-
6.2.1.2 The testing machine shall measure the load to within
mens containing a section of the weld are prepared and tested.
1 %. The testing range shall be so selected that the maximum
Specimens of unwelded sheet are tested and compared to the
load on the specimen falls between 15 and 85 % of the full
welded specimens. The short term weld factor determined is
scale capacity.
compared to the standard (see Table 2), or to the factor agreed
6.2.1.3 The use of autographic equipment to record the load
upon between the supplier and the user.
versus head movement is recommended.
6.2.1.4 Verification of the testing machine shall be made in
5. Significance and Use
accordance with the recommendations of Practices E4.
5.1 The mechanical performance of welded thermoplastic 6.2.2 Micrometer or Vernier Caliper, suitable for measuring
structures is largely dependent on the quality of the welding widthandthicknessofthetestspecimentothenearest0.001in.
operation. It is necessary for fabricators to determine that the (0.025 mm).
proper welding procedures are being followed and that welders
maintain their proficiency. Results from this practice are 7. Test Specimens
indicative of skill in proper welding procedures for different
7.1 Test Pieces For Hot Gas and Extrusion Welding—Start
thermoplastic materials and the use of appropriate welding
with a 10 by 42 in. (250 by 1050 mm) piece of plastic sheet of
equipment. If the welded test specimens have short term weld
the type and thickness to be tested. Cut the sheet as shown in
factors that meet or exceed the minimums as set forth in this
Fig. 1 to yield five pieces, four measuring 5 by 18 in. (125 by
practice, it can be concluded that, with the same degree of skill
450mm)andonemeasuring6by10in.(150by250mm).Two
and diligence by the welder, acceptable welds can be obtained
...