GB/T 26655-2022 Compacted (vermicular) graphite iron castings
1 Scope
This document specifies the designation, ordering information, production methods and chemical composition, technical requirements, test methods, inspection rules, marking, quality certificates, rust prevention, packaging, and storage of compacted (vermicular) graphite iron castings.
This document is applicable to the compacted (vermicular) graphite iron castings cast in a sand mold, or a mold of comparable thermal behavior. This standard may be used as reference for the compacted (vermicular) graphite iron castings produced by other casting methods.
2 Normative references
The following documents contain provisions which, through reference in this text, constitute provisions of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 223.3 Methods for chemical analysis of iron, steel and alloy - The diantipyrylmethane phosphomolybdate gravimetric method for the determination of phosphorus 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 223.86 Steel and iron - Determination of total carbon content - Infrared absorption method after combustion in an induction furnace
GB/T 228.1 Metallic materials - Tensile testing - Part 1: Method of test at room temperature (GB/T 228.1-2010, ISO 6892-1:2009, MOD)
GB/T 231.1 Metallic materials - Brinell hardness test - Part 1: Test method (GB/T 231.1-2018, ISO 6506-1:2014, MOD)
GB/T 4336 Carbon and low-alloy steel - Determination of multi-element contents - Spark discharge atomic emission spectrometric method (routine method)
GB/T 5611 Foundry terminology
GB/T 5612 Code for representing cast iron (GB/T 5612-2018, ISO/TR 15931:2004, MOD)
GB/T 5677 Castings - Radiographic testing
GB/T 6060.1 Surface roughness comparison specimen - Part 1: Casting surface
GB/T 6414 Castings - Dimensional tolerances and geometrical tolerances and machining allowances
GB/T 9443 Steel and iron castings - Liquid penetrant inspection
GB/T 9444 Steel and iron castings - Magnetic particle inspection
GB/T 11351 Mass tolerances of casting
GB/T 15056 Casting surface roughness - Appraising method
GB/T 20123 Steel and iron - Determination of total carbon and sulfur content - Infrared absorption method after combustion in an induction furnace (routine method)
GB/T 24234 Cast iron - Determination of multi-element contents - Spark discharge atomic emission spectrometric method (Routine method)
GB/T 26656 Metallographic test for compacted (vermicular) graphite cast irons
GB/T 34904 Spheroidal graphite iron castings - Ultrasonic testing
GB/T 38441 Pig iron and cast - Determination of chromium, copper, magnesium, manganese, molybdenum, nickel, phosphorus, tin, titanium, vanadium and silicon content - Inductively coupled plasma atomic emission spectrometric method
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 5611 and the following apply.
3.1
compacted (vermicular) graphite cast iron
cast material with the carbon present mainly in the form of precipitated compacted (vermicular) graphite particles embedded in a metallic matrix
3.2
treatments for compacted (vermicular) graphite iron
process that brings the liquid iron with vermiculizer into contact with a substance to produce graphite in the predominantly compacted (vermicular) form during solidification
3.3
relevant wall thickness
section of the casting to which the determined mechanical properties shall apply
3.4
cast sample
test block or test bar that is poured to represent the material properties of the casting
Note: It includes separately cast samples, side-by-side cast samples and cast-on samples.
3.5
side-by-side cast sample
sample cast in the mold alongside the casting, with a joint running system
3.6
test unit; inspection lot; test batch
number of pieces or the tonnage of castings to be accepted or rejected together, on the basis of the tests carried out on test pieces
4 Designation
4.1 The compacted (vermicular) graphite cast iron is designated according to GB/T 5612.
4.2 The grade of material of the compacted (vermicular) graphite cast iron is defined based on the minimum tensile strength value measured from test pieces machined on separately cast samples or side-by-side cast samples with a thickness or diameter of 25mm as shown in Figures 1, 2, and 3.
4.3 Tables 1 and 2 respectively list the tensile strength values measured on test pieces machined from separately cast samples or side-by-side cast samples, and specifies five grades of compacted (vermicular) graphite cast irons. See Annex C. for comparison between grades of compacted (vermicular) graphite cast irons and grades similar to other standards.
4.4 The mechanical properties of castings can also be measured by the following test pieces:
——test pieces machined from cast-on samples: cut and machined on the cast-on sample;
——test pieces machined from samples cut from a casting: cut and machined on the casting sample.
5 Order information
5.1 The following information shall be supplied by the purchaser:
a) designation, quantity and batch size of casting material;
b) type and specification of test piece;
c) technical requirements and test items of castings;
d) requirements for casting surface protection, package, transport and storage;
e) requirements for sample inspection procedures before mass production;
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Designation
5 Order information
6 Production method and chemical composition
7 Technical requirements
8 Test methods
9 Inspection rules
10 Marking, quality certificate, rust prevention, packaging, storage and transportation
Annex A (Informative) Comparison between this document and ISO 16112:2017 in clause/subclause No.
Annex B (Informative) Technical differences between this document and ISO 16112:2017 and their causes
Annex C (Informative) Comparison between grades of compacted (vermicular) graphite iron castings and grades similar to other standards
Annex D (Informative) Properties and typical applications of compacted (vermicular) graphite cast irons
Annex E (Informative) Additional information on properties of compacted (vermicular) graphite cast iron
Annex F (Informative) Evaluation of compacted (vermicular) graphite cast iron nodularity
Annex G (Informative) Technological variables affecting machinability in compacted (vermicular) graphite cast irons
Bibliography
