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GB/T 1348-2019 PDF in English


GB/T 1348-2019 (GB/T1348-2019, GBT 1348-2019, GBT1348-2019)
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GB/T 1348-2019: PDF in English (GBT 1348-2019)

GB/T 1348-2019
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 77.140.80
J 31
Replacing GB/T 1348-2009
Spheroidal Graphite Iron Castings
(ISO 1083:2018, Spheroidal Graphite Cast Irons - Classification, MOD)
ISSUED ON: DECEMBER 31, 2019
IMPLEMENTED ON: JULY 1, 2020
Issued by: State Administration for Market Regulation;
Standardization Administration of the People’s Republic of
China.
Table of Contents
Foreword ... 3 
1 Scope ... 6 
2 Normative References ... 6 
3 Terms and Definitions ... 8 
4 Designations of Spheroidal Graphite Cast Iron ... 9 
5 Order Information ... 9 
6 Manufacturing Methods and Chemical Composition ... 10 
7 Technical Requirements ... 10 
8 Preparation of Test Specimens ... 17 
9 Test Methods ... 25 
10 Inspection Rules ... 28 
11 Marking and Quality Certificate ... 30 
12 Rust Prevention, Packaging and Storage ... 31 
Appendix A (informative) Structural Changes of this Standard Compared with
ISO 1083:2018 ... 32 
Appendix B (informative) Supplementary Information of Solid Solution
Strengthened Ferritic Spheroidal Graphite Cast Iron ... 34 
Appendix C (informative) Guideline Values of Mechanical Properties of Casting
Body Specimens ... 38 
Appendix D (normative) Difference of Elongation Measured when Lo = 5d and
Lo = 4d ... 41 
Appendix E (informative) Classification by Hardness ... 43 
Appendix F (informative) Spheroidization Rate (or spheroidal graphite ratio) 47 
Appendix G (informative) Mechanical Properties and Physical Properties of
Spheroidal Graphite Cast Iron Materials ... 48 
Appendix H (informative) Procedures of Cutting Test Specimens ... 51 
Appendix I (informative) A Comparison Table of Material Designations of
Domestic and Overseas Spheroidal Graphite Cast Iron ... 52 
Spheroidal Graphite Iron Castings
1 Scope
This Standard specifies the designations, order information, manufacturing methods,
chemical composition, technical requirements, sample preparation, test methods,
inspection rules, marking, quality certificate, rust prevention, packaging and storage of
spheroidal graphite iron castings.
This Standard is applicable to ordinary or low-alloy ferritic to pearlitic spheroidal
graphite iron castings and solid solution strengthened ferritic spheroidal graphite iron
castings cast in sand molds or casting molds with thermal conductivity equivalent to
sand molds. Spheroidal graphite iron castings manufactured through special casting
methods may also take this Standard as a reference.
This Standard is inapplicable to spheroidal graphite cast iron pipes, spheroidal graphite
cast iron pipe fittings, parts and joints;
This Standard is inapplicable to Austenitic spheroidal graphite cast iron;
This Standard is inapplicable to Ausferrite spheroidal graphite cast iron (austempered
spheroidal graphite cast iron).
2 Normative References
The following documents are indispensable to the application of this document. In
terms of references with a specified date, only versions with a specified date are
applicable to this document. In terms of references without a specified date, the latest
version (including all the modifications) is applicable to this document.
GB/T 223.3 Methods for Chemical Analysis of Iron, Steel and Alloy - The Diantipyryl
Methane Phosphomolybdate Gravimetric Method for the Determination of
Phosphorous Content
GB/T 223.4 Alloyed Steel - Determination of Manganese Content - Potentiometric or
Visual Titration Method
GB/T 223.60 Methods for Chemical Analysis of Iron, Steel and Alloy - The Perchloric
Acid Dehydration Gravimetric Method for the Determination of Silicon Content
GB/T 223.72 Iron, Steel and Alloy - Determination of Sulfur Content - Gravimetric
Method
GB/T 34904 Spheroidal Graphite Iron Castings - Ultrasonic Testing
3 Terms and Definitions
What is defined in GB/T 5611, and the following terms and definitions are applicable to
this document.
3.1 Spheroidal Graphite Cast Iron
Spheroidal graphite cast iron refers to cast iron with iron, carbon and silicon as the
basic elements, and with carbon mainly exists in the form of spheroidal graphite.
3.2 Ferritic to Pearlitic Spheroidal Graphite Cast Iron
Ferritic to pearlitic spheroidal graphite cast iron refers to spheroidal graphite cast iron
which contains ferrite or pearlite, or a mixed matrix of ferrite and pearlite.
3.3 Graphite Spheroidizing Treatment
Spheroidizing Treatment
Graphite Spheroidizing treatment refers to a technological process, in which,
spheroidizing agent is added to molten iron, so that carbon mainly precipitates in the
form of spheroidal graphite during the solidification of the molten iron.
3.4 Relevant Wall Thickness
Relevant wall thickness refers to the section thickness of casting representing the
mechanical properties of the casting materials.
3.5 Cast Sample
Cast sample refers to a test specimen representing the properties of the casting
materials, including single-cast sample, side-by-side cast sample and attached cast
sample.
3.6 Side-by-side Cast Sample
Side-by-side cast sample refers to a cast sample that uses the same casting system
as the casting and is cast side by side with the casting.
3.7 Solid Solution Strengthened
Solid solution strengthened refers to the phenomenon that solute atoms dissolve into
the metal matrix to form a solid solution, which increases the strength and hardness of
the metal.
3.8 Solid Solution Strengthened Ferritic Spheroidal Graphite Cast Iron
a) Designation of casting materials;
b) Any special requirements (including the location of the relevant wall thickness)
shall be negotiated and determined by the demand-side and the supply-side.
5.2 All order requirements shall be negotiated and determined by the demand-side and
the supply-side at the same time that the order is accepted.
6 Manufacturing Methods and Chemical Composition
6.1 The manufacturing methods and chemical composition of spheroidal graphite cast
iron shall be determined by the supply-side on its own. The chemical composition of
spheroidal graphite cast iron shall not be used as the basis for the acceptance
inspection of castings.
6.2 In terms of ferritic to pearlitic spheroidal graphite iron castings, the degree of the
mechanical properties depends on the ratio of ferrite to pearlite. Generally speaking,
the ratio of ferrite to pearlite is adjusted through the adjustment of the alloy content or
the mode of thermal treatment.
6.3 The mechanical properties of solid solution strengthened ferritic spheroidal
graphite cast iron depend on the degree of solid solution strengthening of the ferrite
matrix. The degree of solid solution strengthening mainly depends on the silicon
content. The chemical composition and physical properties of solid solution
strengthened ferritic spheroidal graphite cast iron may take Appendix B as a reference.
7 Technical Requirements
7.1 General Rules
7.1.1 The performance index values listed in this Standard are the performance values
of spheroidal graphite cast iron cast with sand molds or casting molds with thermal
conductivity equivalent to sand molds. Upon agreement between the demand-side and
the supply-side, it may also be used for spheroidal graphite cast iron cast by other
methods.
7.1.2 The designation of casting materials is determined based on the minimum
mechanical properties of a cast sample with a thickness or diameter of 25 mm. The
designation is irrelevant to the type of the cast sample.
7.2 Ferritic to Pearlitic Spheroidal Graphite Cast Iron
7.2.1 Cast sample
7.2.1.1 Tensile properties
properties of the casting body test specimen shall take Appendix C as a reference.
NOTE 1: the property values of the casting body test specimen cannot be unified, because
they depend on the complexity of the casting and the variation of the wall
thickness.
NOTE 2: the mechanical property values of the casting body test specimen are affected
by not only the material properties, but also the defects of the sampling location.
7.2.3 Classification by hardness
Upon agreement between the demand-side and the supply-side, classification may be
conducted by hardness. Please take Appendix E as a reference.
7.2.4 Graphite morphology
7.2.4.1 Graphite is mainly in the form of Type-VI and Type-V. The spheroidizing level
shall be not lower than Level-3 spheroidizing specified in GB/T 9441. More precise
graphite morphologies and spheroidizing levels shall be negotiated and determined by
the demand-side and the supply-side.
7.2.4.2 Graphite morphology may be determined through the method of observing
metallographic specimens or non-destructive testing. When there are objections, the
metallographic detection method shall prevail.
NOTE: Appendix F provides more reference documents regarding the spheroidization rate.
7.2.5 Matrix structure
Generally speaking, the requirements for matrix structure are determined by the
supply-side. If there are special requirements, then, they shall be negotiated and
determined by the supply-side and the demand-side. Table G.1 in Appendix G provides
reference documents of matrix structures.
7.3 Solid Solution Strengthened Ferritic Spheroidal Graphite Cast Iron
7.3.1 Cast specimen
The tensile properties of cast specimen of solid solution strengthened ferritic
spheroidal graphite cast iron shall comply with the stipulations of Table 3.
Upon agreement between the demand-side and the supply-side, classification may be
conducted by hardness. Please take Appendix E as a reference.
7.3.4 Graphite morphology
7.3.4.1 Graphite is mainly in the form of Type-VI and Type-V. The spheroidizing level
shall be not lower than Level-3 spheroidizing specified in GB/T 9441. More precise
graphite morphologies and spheroidizing levels shall be negotiated and determined by
the demand-side and the supply-side.
7.3.4.2 Graphite morphology may be determined through the method of observing
metallographic specimens or non-destructive testing. When there are objections, the
metallographic detection method shall prevail.
NOTE: Appendix F provides more reference documents regarding the spheroidization rate.
7.3.5 Matrix structure
The requirements for matrix structure are negotiated and determined by the demand-
side and the supply-side. Table G.1 in Appendix G provides reference documents of
the main matrix structures.
7.4 Geometric Shapes and Dimensional Tolerances
7.4.1 The geometric shapes and dimensions of the castings shall comply with the
stipulations of the drawings.
7.4.2 The dimensional tolerances of the castings shall comply with the stipulations of
GB/T 6414. When there are special requirements, comply with the drawings or relevant
technical requirements.
7.5 Mass Tolerances
The mass tolerances of the castings shall comply with the relevant stipulations of GB/T
11351. When there are special requirements, comply with the drawings or relevant
technical requirements.
7.6 Surface Quality of Casting
7.6.1 The castings shall be cleaned up; the excess parts shall be trimmed.
7.6.2 The requirements for the removal of casting riser residues, sticky sand, oxide
scale and internal cavity residues shall comply with the technical specifications, or, the
order agreement between the demand-side and the supply-side.
7.6.3 After using the plasma method to cut the castings, the heat affected zone shall
be processed away.
9.6 Geometric Shapes and Dimensional Tolerances
9.6.1 The geometric shapes and dimensional tolerances of the castings shall be
inspected in accordance with the requirements of 7.4.
9.6.2 For the first batch of castings, in accordance with the drawings, inspect the
dimensions and geometric shapes of the castings piece by piece. Castings
manufactured through methods that can ensure the dimensional stability may be spot-
checked; the frequency and quantity of the spot-checks shall be negotiated and
determined by the demand-side and the supply-side.
9.6.3 For castings in mass manufacturing, the frequency and quantity of the
inspections shall be negotiated and determined by the demand-side and the supply-
side.
9.7 Chemical Composition Analysis
9.7.1 When the demand-side has requirements for the chemical composition of the
castings, they shall be implemented in accordance with the technical requirements of
the demand-side. If there is no stipulation in the technical requirements of the demand-
side, the chemical composition shall be determined by the supply-side on its own.
9.7.2 Spectrochemical analysis shall be performed in accordance with the stipulations
of GB/T 24234.
9.7.3 The conventional chemical composition analysis methods of castings shall
comply with the stipulations of GB/T 223.3, GB/T 223.4, GB/T 223.60, GB/T 223.72,
GB/T 223.83 and GB/T 223.86.
9.8 Non-destructive Testing
9.8.1 Magnetic particle testing shall be conducted in accordance with the stipulations
of GB/T 9444.
9.8.2 Penetrant testing shall be conducted in accordance with the stipulations of GB/T
9443.
9.8.3 Ultrasonic testing shall be conducted in accordance with the stipulations of GB/T
34904.
9.8.4 Radiographic testing shall be conducted in accordance with the stipulations of
GB/T 5677.
9.9 Defects
9.9.1 The surface defects of the castings may be visually inspected. When the
demand-side has special requirements, the method of magnetic particle testing or
penetrant testing may also be used.
the manufacturing process combines the sampling batches and takes supporting
measures in advance. During in-mold spheroidizing treatment, the size of the sampling
batch and the test quantity shall be negotiated and determined by the demand-side
and the supply-side when the order is accepted.
10.3 Re-inspection
10.3.1 Re-inspection conditions
If the result of the first inspection cannot satisfy the requirements for the mechanical
properties of the materials, re-inspection is allowed.
10.3.2 Validity of inspection
10.3.2.1 When due to one of the following reasons, the inspection result does not
satisfy the requirements, then, the inspection is invalid:
a) Improper loading of the test specimen on the testing machine, or, improper
operation of the testing machine;
b) There are casting defects on the surface of the test specimen, or, improper
machining of the test specimen (for example, non-conformant specimen size,
transition fillet and roughness);
c) The tensile specimen breaks beyond the gauge length;
d) There are obvious casting defects on the fracture of the tensile specimen.
10.3.2.2 Under the above-mentioned circumstances, conduct re-sampling on the same
cast sample, or, conduct re-sampling on the same casting batch of cast samples, then,
conduct re-inspection. The result of the re-inspection shall replace the result of the
invalid inspection.
10.3.2.3 The result of the re-inspection shall be considered as the final inspection result.
10.4 Evaluation of Inspection Result
10.4.1 During the inspection of mechanical properties, firstly, use one tensile specimen
for the inspection. If it complies with the requirements, then, the batch of castings is
qualified in terms of texture; if the inspection result fails to comply with the requirements,
and the failure is not caused by reasons listed in 10.3.2.1, then, take another two
specimens from the same batch of specimens for the re-inspection.
10.4.2 During the impact test, if the impact absorption energy of three impact
specimens complies with the requirements, then, the batch of castings is qualified in
terms of impact performance; if the test result of one specimen fails to reach the
minimum value, then, double-take three spare impact specimens from the same batch
for the test; add the result to the original result, so as to re-calculate the average value.
strength, yield strength, elongation and Brinell hardness of each test
specimen. When the demand-side and the supply-side obtain the desired
statistical confidence, corresponding to each Brinell hardness value, in order
to obtain a minimum tensile strength, multiple tests may be performed.
e) Draw a histogram of the property of tensile strength as one of the functions of
hardness.
f) For each Brinell hardness value, select the corresponding minimum tensile
strength value as the index of the process capability.
g) List one-by-one the minimum hardness value of each designation of material
that satisfies the tensile strength and yield strength value in Table 1 and Table
3.
h) List one-by-one the maximum hardness value of each designation of material
that satisfies the elongation value in Table 1 and Table 3.
The hardness ranges of the maximum and minimum Brinell hardness values shall be
determined in accordance with the above procedures.
E.4 Requirements for Sampling
Each hardness test may be performed on a test bar, or, a position on the casting body
agreed by the demand-side and the supply-side. When there is no agreement between
the demand-side and the supply-side, the supply-side may choose to conduct sampling
in a representative position on the casting.
E.5 Test Methods
E.5.1 The test method for hardness shall comply with the stipulations of GB/T 231.1.
E.5.2 If it is impossible to test the hardness on the casting body, through the negotiation
and determination between the demand-side and the supply-side, the hardness may
also be tested on attached cast sample or single-cast sample.
E.5.3 If the casting requires thermal treatment, the attached cast bar (sample) shall be
cut after the casting receives the thermal treatment.
E.5.4 If a test specimen is cut from a single-cast sample for the hardness test, when
the casting has any requirements for thermal treatment, the cast sample shall receive
the thermal treatment together with the casting that it represents.
E.6 Frequency and Quantity of Hardness Tests
The frequency and quantity of hardness tests shall be determined by the demand-side
and the supply-side through negotiation.
Appendix F
(informative)
Spheroidization Rate (or spheroidal graphite ratio)
The spheroidization rate of spheroidal graphite cast iron is defined as the percentage
of spheroidal graphite and nodular graphite. The spheroidization rate may be
determined by the following three methods:
---Comparing with the schematic diagram of graphite particle morphology in GB/T
9441, estimate the percentage of Type-V and Type-VI graphite spheres.
---Under a metallographic microscope, adopt the method of visual observation to
compare the mapping of graphite morphology of spheroidal graphite cast iron.
---Through automatic image analysis, determine the percentage of the area of
Type-V and Type-VI graphite in the area of all graphite particles.
This percentage is usually obtained by cutting the test specimen on the cross-section,
and then, polishing it and observing it at 100 times; it may also be obtained by image
analysis at a relatively high magnification; it may also be obtained after pre-calibration
by measuring the speed of ultrasonic sound passing through the material.
The spheroidization degree depends on not only the manufacturing processing (charge,
residual magnesium and inoculation mode, etc.), but also the cooling modulus of the
casting section. In addition, some deteriorated graphite is related to the mold.
Even for materials with a given cooling modulus, it is impossible to accurately
determine the minimum characteristic value that generates the critical spheroidization
degree. That is because the variation of the spheroidization degree is related to not
only the used determination method, but also the material designation (especially the
chemical composition of the material) of the casting and the amount of graphite per
unit area.
However, 80% ~ 85% or higher spheroidization rate can usually guarantee the
minimum tensile property value specified in the Standard (a higher yield strength RP0.2).
Most of 15% ~ 20% graphite is not spheroidal or nodular, but temper graphite, and
some might be vermicular graphite.
The castings need to withstand a variety of loads, especially that a higher
spheroidization rate (including the percentage of spheroidal and nodular graphite) is
required in the fatigue state. For special castings and material designations, the
requirement for a higher spheroidization rate shall be evaluated through experimental
research.
......
 
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.