ISO/TR 10809-1:2023 鋳鉄 — Part 1: 設計のための材料と特性 | ページ 6

3.1

alloying

addition of elements such as copper, nickel and molybdenum to enhance hardenability

3.2

annealing

heat treatment (3.17) that breaks down iron carbide (3.21) and pearlite (3.26) to produce ferrite (3.12)

3.3

ausferrite

cast iron matrix microstructure, produced by a controlled thermal process, which consists of predominantly acicular ferrite (3.12) and high carbon austenite (3.5)

3.4

austempering

<of spheroidal graphite cast iron> heat treatment (3.17) , consisting of heating the castings to a temperature at which austenite (3.5) starts to form during heating and holding a sufficient time for carbon diffusion into the austenite, followed by cooling at a rate sufficient to avoid the formation of pearlite (3.26) , and transforming the matrix structure for a time and temperature (above the martensite (3.23) start temperature) sufficient to produce the desired properties

Note 1 to entry: This process produces a microstructure that consists predominantly of acicular ferrite (3.12) and high carbon austenite. This microstructure is called ausferrite (3.3) . Examples of ausferritic microstructures are given in ISO/TR 945-3.

[SOURCE:ISO 17804:2020, 3.3]

3.5

austenite

cast iron matrix microstructure, formed in cast irons immediately upon solidification that at lower temperatures transforms into ferrite (3.12) , pearlite (3.26) , ausferrite (3.3) and/or martensite (3.23) , unless the austenite is stabilized at lower temperatures by either sufficient alloying (3.1) with nickel in austenitic cast irons, or by carbon enrichment in the austenite phase during the austempering (3.4) of ausferritic cast irons containing sufficient silicon to prevent formation of bainite (3.6)

3.6

bainite

cast iron matrix microstructure that can form if a white iron with low silicon content is austempered (3.4)

Note 1 to entry: Ausferritic cast irons contain sufficient silicon to prevent the formation of bainite.

3.7

carbon equivalent

formula based on the carbon and silicon contents of molten cast iron by thermal analysis

3.8

compacted

stubby form of graphite flakes providing material properties in between those of the grey and spheroidal graphite irons

3.9

ductility

elongation measured on the tensile test piece following testing

Note 1 to entry: It is expressed as a percentage.

3.10

eutectic

point at which elements are present at a level where the lowest solidification temperature is reached

3.11

eutectic cell

solidification mechanism in grey cast iron where cells form, each with its individual internal graphite structure

Note 1 to entry: These ultimately coalesce to form a uniform material.

3.12

ferrite

cast iron matrix microstructure formed during slow cooling of austenite (3.5) , provided that pearlite (3.26) is not rapidly forming to consume the austenite

Note 1 to entry: The formation of ferrite is promoted by both slower cooling and higher silicon content. The latter results in considerable substitutional solution strengthening of the ferrite. A new kind of ferrite, also interstitially solution strengthened by medium carbon contents, is formed during austempering (3.4) into ausferritic microstructures.

3.13

graphite flake

two-dimensional appearance of the graphite form (3.14) in grey cast iron, when looking at the material structure through a microscope

3.14

graphite form

descriptor of graphite shape, which can define material properties

Note 1 to entry: It is shown in ISO 945-1.

3.15

graphite size

size of the free graphite, whether in the form of flakes, nodules, temper nodules or vermicular graphite

Note 1 to entry: It can be quantified using the relevant cast iron type standard, and will have an effect on the mechanical properties of the final product.

Note 2 to entry: It is classified in accordance with ISO 945-1.

Note 3 to entry: Fine graphite normally provides better properties than coarse graphite.

3.16

hardening

heat treatment (3.17) that generally produces martensite (3.23) in the matrix (3.24)

3.17

heat treatment

thermal process that removes internal stress or enhances properties

3.18

hypoeutectic

composition below the eutectic (3.10)

3.19

hypereutectic

composition above the eutectic (3.10)

3.20

inoculation

technique of adding inoculant to molten iron to enhance the graphite growth

3.21

iron carbide

iron and carbon in a combined form

3.22

iron-chromium carbide

complex carbide principally found in abrasion-resisting irons

3.23

martensite

cast iron matrix microstructure formed from cooling any austenite (3.5) not previously transformed at higher temperatures into ferrite (3.12) , pearlite (3.26) , bainite (3.6) and/or ausferrite (3.3)

Note 1 to entry: In contrast to these transformations relying on the diffusion of carbon and thus depending on both temperature and time, the formation of martensite is diffusionless and is dependent only on temperature.

3.24

matrix

structural phases surrounding the graphite in graphitic cast irons and carbide in abrasion-resisting irons

3.25

nodularity

assessment of the proportion of spheroidal graphite particles in a cast iron sample

Note 1 to entry: Nodularity is generally expressed as a percentage.

[SOURCE:ISO 945-4:2019, 3.5]

3.26

pearlite

cast iron two-phased lamellar matrix microstructure composed of alternating layers of ferrite (3.12) and cementite (Fe3C), formed by a eutectoid reaction during slow cooling of austenite (3.5) not previously transformed into ferrite

Note 1 to entry: The formation of pearlite is promoted by both faster cooling and lower silicon content.

3.27

quenching

rapid cooling of previously austenitized castings to prevent formation of ferrite (3.12) and pearlite (3.26) , cooled either in a salt bath for subsequent austempering (3.4) into ausferrite (3.3) or in oil to form martensite (3.23)

3.28

relevant wall thickness

section thickness of the casting, agreed between the manufacturer and the purchaser, to which the determined mechanical properties apply

[SOURCE:ISO 185:2020, 3.2, modified — “thickness” added before “section”.]

3.29

section sensitivity

change in material properties that occurs due to variations in the solidification and cooling rates of cast iron poured into different wall section thicknesses

3.30

spheroidal graphite

graphite in spheroidal graphite iron that is present as spheroids as opposed to flakes

3.31

stress relieving

low-temperature heat treatment (3.17) that removes stress without affecting structure

3.32

tempering

heat treatment (3.17) that enhances properties or relieves stress after hardening (3.16)

3.33

temper carbon

graphite form (3.14) found in malleable iron with the appearance of “ragged” spheroids, also known as “temper carbon nodules”

3.34

trace elements

elements that are present in small amounts

Note 1 to entry: Such elements can also be added for alloying (3.1) purposes.