ASTM C660-81(2015)
(Practice)Standard Practices for Production and Preparation of Gray Iron Castings for Porcelain Enameling
Standard Practices for Production and Preparation of Gray Iron Castings for Porcelain Enameling
ABSTRACT
These practices are intended for production and preparation of gray iron castings for porcelain enamelling. Design of the casting should be such as to minimize variations in temperature during firing and cooling. The governing factors in pattern layout and shop control are elimination of discontinuities, chill, and inclusions at or near the surfaces to be coated. Visual inspection methods for enamelling surfaces should place emphasis on the detection and remedy of porosity, sand inclusions, and gas holes. Porosity consisting of essentially subsurface pinholes, shallow covered blows, body scars, or shrinkage near the surface may or may not be acceptable for correction, depending upon severity.
SCOPE
1.1 These practices are intended to indicate certain casting characteristics and pre-enameling practices which will facilitate finishing by the wet- or dry-process methods of porcelain enameling. All of the listed recommendations are based on experiences with gray iron casting and enameling.
1.2 The values stated in inch-pound 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 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 establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: C660 − 81 (Reapproved 2015)
Standard Practices for
Production and Preparation of Gray Iron Castings for
1
Porcelain Enameling
This standard is issued under the fixed designation C660; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
Porcelain-enameled gray iron is a composite of a vitreous or glassy inorganic coating, bonded to a
casting by fusion at temperatures above 800 °F (425 °C). Porcelain enamels are a family of coatings
available in a wide variety of compositions and properties, but all are characterized by their glass-like
nature. Selection of an appropriate porcelain enamel must be made on the basis of the end-use
requirements. Certain casting design features and processing considerations can facilitate the
application and efficient use of the selected enamel.
Two general types of enamels are available for use on cast iron. These are commonly referred to
as wet-process and dry-process enamels (see Terminology C286). In wet-process enameling, a slurry
of wet-ground materials is dipped or sprayed on the casting, the water removed by drying, and the
coatingmaturedbyheatinginafurnaceforsufficienttimetobringaboutfusionoftheglassyparticles.
In dry-process enameling, dry-powdered glassy material is applied by dusting onto a redhot casting
that has been ground-coated by the wet process prior to firing. The partially matured dusted coating
is returned to the furnace to complete the fusion process. In general, wet-process enamels are thinner
over-all than dry-process enamels.
1. Scope 2. Referenced Documents
2
1.1 These practices are intended to indicate certain casting 2.1 ASTM Standards:
characteristics and pre-enameling practices which will facili- A48/A48MSpecification for Gray Iron Castings
tate finishing by the wet- or dry-process methods of porcelain A74Specification for Cast Iron Soil Pipe and Fittings
enameling. All of the listed recommendations are based on A126 Specification for Gray Iron Castings for Valves,
experiences with gray iron casting and enameling. Flanges, and Pipe Fittings
A278/A278M Specification for Gray Iron Castings for
1.2 The values stated in inch-pound units are to be regarded
Pressure-Containing Parts for Temperatures Up to 650°F
as standard. The values given in parentheses are mathematical
(350°C)
conversions to SI units that are provided for information only
C286 Terminology Relating to Porcelain Enamel and
and are not considered standard.
Ceramic-Metal Systems
1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
3. Recommended Casting Characteristics
responsibility of the user of this standard to establish appro-
3.1 Design of the casting should be such as to minimize
priate safety and health practices and determine the applica-
variations in temperature during firing and cooling. Section
bility of regulatory limitations prior to use.
thickness should be uniform to eliminate possible warping and
fire cracking of castings; to facilitate an even rate of heating
1
ThesepracticesareunderthejurisdictionofASTMCommitteeB08onMetallic
andInorganicCoatingsandarethedirectresponsibilityofSubcommitteeB08.12on
2
Materials for Porcelain Enamel and Ceramic-Metal Systems. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved May 1, 2015. Published June 2015. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approvedin1970.Lastpreviouseditionapprovedin2010asC660–81(2010).DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/C0660-81R15. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
C660 − 81 (2015)
and cooling and to prevent possible spalling, hairlining, and 4.2.3 Manganese content of the iron must be sufficient to
blistering of the porcelain enamel. balance the sulfur content. A slight excess of manganese is
preferred in order to assure sulfur tie-up; that is, Mn, per-
3.2 When a variation in section thickness is unavoidable,
cent=(1.7×S, percent)+0.3.
the transition of the two sections should be gradual and
4.2.4 High phosphorus content of 0.70 % may be desirable
smooth. Abrupt changes in sections give rise to significant
for improved strength at enameling temperatures. Phosphorus
differences in heating and cooling rates, resulting in nonuni-
in the iron has no reported association with boiling defects in
form coating conditions.
the coating.
3
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
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: C660 − 81 (Reapproved 2010) C660 − 81 (Reapproved 2015)
Standard Practices for
Production and Preparation of Gray Iron Castings for
1
Porcelain Enameling
This standard is issued under the fixed designation C660; 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.
INTRODUCTION
Porcelain-enameled gray iron is a composite of a vitreous or glassy inorganic coating, bonded to a
casting by fusion at temperatures above 800 °F (425 °C). Porcelain enamels are a family of coatings
available in a wide variety of compositions and properties, but all are characterized by their glass-like
nature. Selection of an appropriate porcelain enamel must be made on the basis of the end-use
requirements. Certain casting design features and processing considerations can facilitate the
application and efficient use of the selected enamel.
Two general types of enamels are available for use on cast iron. These are commonly referred to
as wet-process and dry-process enamels (see Terminology C286). In wet-process enameling, a slurry
of wet-ground materials is dipped or sprayed on the casting, the water removed by drying, and the
coating matured by heating in a furnace for sufficient time to bring about fusion of the glassy particles.
In dry-process enameling, dry-powdered glassy material is applied by dusting onto a redhot casting
that has been ground-coated by the wet process prior to firing. The partially matured dusted coating
is returned to the furnace to complete the fusion process. In general, wet-process enamels are thinner
over-all than dry-process enamels.
1. Scope
1.1 These practices are intended to indicate certain casting characteristics and pre-enameling practices which will facilitate
finishing by the wet- or dry-process methods of porcelain enameling. All of the listed recommendations are based on experiences
with gray iron casting and enameling.
1.2 The values stated in inch-pound 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 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 establish appropriate safety and health practices and determine the applicability of regulatory
limitations prior to use.
2. Referenced Documents
2
2.1 ASTM Standards:
A48/A48M Specification for Gray Iron Castings
A74 Specification for Cast Iron Soil Pipe and Fittings
A126 Specification for Gray Iron Castings for Valves, Flanges, and Pipe Fittings
A278/A278M Specification for Gray Iron Castings for Pressure-Containing Parts for Temperatures Up to 650°F (350°C)
C286 Terminology Relating to Porcelain Enamel and Ceramic-Metal Systems
1
These practices are under the jurisdiction of ASTM Committee B08 on Metallic and Inorganic Coatings and are the direct responsibility of Subcommittee B08.12 on
Materials for Porcelain Enamel and Ceramic-Metal Systems.
Current edition approved April 1, 2010May 1, 2015. Published June 2010June 2015. Originally approved in 1970. Last previous edition approved in 20052010 as
C660 – 81 (2005). (2010). DOI: 10.1520/C0660-81R10.10.1520/C0660-81R15.
2
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.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
C660 − 81 (2015)
3. Recommended Casting Characteristics
3.1 Design of the casting should be such as to minimize variations in temperature during firing and cooling. Section thickness
should be uniform to eliminate possible warping and fire cracking of castings; to facilitate an even rate of heating and cooling and
to prevent possible spalling, hairlining, and blistering of the porcelain enamel.
3.2 When a variation in section thickness is unavoidable, the transition of the two sections should be gradual and smooth. Abrupt
changes in sections give rise to significant differences in heating and cooling rates, resulting in nonuniform coating con
...
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