ISO 28401:2024 軽金属およびその合金 — チタンおよびチタン合金 — 語彙 | ページ 6

3.1.1

チタンスポンジ

金属チタンを多孔質でスポンジ状にした製品で、金属チタンの溶解原料として使用されます。

注記 1:スポンジチタンを製造するには、酸化チタン鉱石を四塩化物に塩素化し、濃縮して精製します。次に、生成物は不活性雰囲気下でマグネシウムまたはナトリウムで還元されます。

3.1.2

合金

基本的な金属元素と合金元素や不純物などの他の元素の混合物からなる金属物質

注記 1:この文書では、質量分率で最も支配的な元素はチタンです。

3.1.3

合金元素

特別な特性を与えるために、卑金属に意図的に添加または保持される金属または非金属元素

3.1.4

不純物

存在しているが、意図的に金属に添加または保持されていない金属または非金属元素

3.1.5

鍛造合金

主に熱間および/または冷間塑性加工による鍛造製品の製造を目的とした合金

3.1.6

鋳造合金

主に鋳物の製造を目的とした合金

3.1.7

マスターアロイ

融点、密度、溶解性などの物理的特性を制御することによって、溶融または圧縮されたチタンに添加される元素を合金化することを目的とした合金

3.1.8

熱処理可能な合金

適切な熱処理によって強化できる合金

3.1.9

非熱処理合金

熱処理ではなく冷間加工のみで強化できる合金

3.2.1

α phase

solid solution at low temperature with a hexagonal closed packed crystal structure

3.2.2

α phase stabilisers

alloy elements such as aluminium, oxygen, nitrogen and carbon that expand the α phase, which is the low temperature phase of titanium alloy, to high temperature and enhance the stability of the α structure

3.2.3

β phase

solid solution at high temperature with a body centred cubic crystal structure

3.2.4

β phase stabilisers

alloy elements such as iron, manganese, molybdenum and vanadium that expand the β phase, which is the high temperature phase of titanium alloy, to low temperature and enhance the stability of the β structure

3.2.5

α plus β phase

mixture of the α and β phases

3.2.6

β-transus temperature

temperature above which the crystal structure turns to the β phase

3.3.1

microstructure by morphology

microstructure observed by an optical and/or a scanning microscope characterized by composition, processing and heat treating

Note 1 to entry: See Reference [2] for detailed classifications of titanium and titanium alloy microstructures, including microstructure photographs.

3.3.2

equiaxed α structure

polygonal or globular α structure with approximately equal dimensions in all directions

Note 1 to entry: In some types of α-β titanium alloys, most α structures are observed in a globular rather than equiaxed form. Therefore, this structure is sometimes called the globular α structure.

3.3.3

acicular α structure

microstructure in which β transforms the selected crystal planes by nucleation and growth or martensitically

Note 1 to entry: This microstructure is also called the Widmansttäten α structure.

Note 2 to entry: Depending on the aspect ratio and the existence state in the colonies, other names for this microstructure are platelet α structure, blocky α structure, basketweave α structure and lamellar α structure.

3.3.4

grain boundary α structure

α structure formed at prior β grain boundaries during cooling from the single β phase region

3.3.5

elongated α structure

grain microstructure in which the length of one of the three axial directions of the crystal grains is remarkably elongated

Note 1 to entry: The structure shows that the influence of plastic working remains strong or that it has failed to become equiaxed and remained elongated.

Note 2 to entry: The string-like elongated structure is sometimes called stringy α structure.

3.3.6

bimodal structure

microstructure composed of equiaxed or elongated α structure embedded in transformed β matrix

3.4.1

unwrought product

general term for products obtained by either melting, casting or powder metallurgy processes or a combination thereof

3.4.2

electrode for remelting

cylindrical or rectangular semi-product formed from titanium sponge and alloying elements or consolidated from recycled and processed scrap, to be remelted once or multiple cycles in a vacuum or in inert gas for at least the final melting

3.4.3

ingot for rolling, extruding and forging

titanium and titanium alloy ingot melted mostly using the vacuum arc remelting (VAR) method applied for at least the final cycle in a vacuum or in inert gas, suitable for rolling, extruding and forging

Note 1 to entry: The melting method is not necessarily limited to VAR. It also includes cases that involve electron beam melting (EBM), plasma arc melting (PAM) and others.

Note 2 to entry: The VAR method is the typical method used for melting titanium and titanium alloys. In this method, the titanium or titanium alloy electrode is dissolved while being consumed itself by an arc generated between a consumable electrode and a water-cooled copper crucible in a vacuum or in an inert gas environment.

Note 3 to entry: The EBM method is also called electron beam cold hearth melting. In this method, charged titanium or titanium alloy is melted in a water-cooled copper hearth using an electron gun and then poured into a mould in a vacuum or in an inert gas chamber.

Note 4 to entry: The PAM method is the method for melting metal using arc discharge generated between the electrode of a plasma torch and the metal, and by using a gas such as argon or helium as the plasma gas. In this method, metal can be melted in an inert gas atmosphere under the environment close to atmospheric pressure.

3.4.4

ingot for remelting

titanium and titanium alloy ingot in a form suitable for remelting after having been processed metallurgically for composition, melted by electron beam melting, vacuum arc remelting and plasma arc melting and other methods applied for at least the final cycle in a vacuum or in inert gas

3.4.5

additive manufacturing product

articles manufactured by 3D metal printing

3.5.1

wrought product

general term for products obtained by hot and/or cold plastic deformation processes, such as extruding, forging, hot rolling, cold rolling or drawing, either solely or in combination

3.5.2

billet

solid wrought product of uniform cross-section that is above 10 000 mm² along its whole length, supplied in straight lengths

Note 1 to entry: The cross-sections are in the shape of circles, ovals, squares, rectangles, equilateral triangles or regular polygons. Products with a square, rectangular, triangular or polygonal cross-section can have corners rounded along their whole length.

3.5.3

rod/bar

solid wrought product of uniform cross-section that is under 10 000 mm² along its whole length, supplied in straight lengths.

Note 1 to entry: The cross-sections are in the shape of circles, ovals, squares, rectangles, equilateral triangles or regular polygons. Products with a square, rectangular, triangular or polygonal cross-section can have corners rounded along their whole length.

3.5.4

wire

solid wrought product of uniform cross-section along its whole length, supplied in coiled form

Note 1 to entry: The cross-sections are in the shape of circles, ovals, squares, rectangles, equilateral triangles or regular polygons. Products with a square, rectangular, triangular, or polygonal cross-section can have corners rounded along their whole length.

3.5.5

wire rod

intermediate unwrought or wrought product for wire

3.5.6

drawing stock

intermediate solid wrought product of uniform cross-section along its whole length supplied in coiled form for drawing

Note 1 to entry: The cross-sections are approximately round, triangular or regular polygonal with dimensions usually exceeding 5 mm.

3.5.7

tube

hollow wrought product of uniform cross-section with only one enclosed hollow space along its whole length, and with a uniform wall thickness, supplied in straight lengths or in coiled form

Note 1 to entry: The cross-sections are in the shape of circles, ovals, squares, rectangles, equilateral triangles or regular polygons. Hollow products with square, rectangular, equilateral triangular or regular polygonal cross-sections, which can have corners rounded along their whole length, are also to be considered as tubes, provided the inner and outer peripheries are concentric and have the same form and orientation.

Note 2 to entry: Tubes can also be formed by piercing trespassing and by forming and joining sheet or strip.

Note 3 to entry: Bent, threaded, drilled, waisted, expanded and cone-shaped hollow products are classified as tubes.

3.5.8

profile/shape

wrought product of uniform cross-section along its whole length, with a cross-section other than rod/bar, wire, tube, sheet, plate or strip, supplied in straight lengths or in coiled form

3.5.9

plate

flat-rolled product of rectangular cross-section with uniform thickness over 4,75 mm, supplied in straight lengths (i.e., flat) usually with sheared, sawn or flame-cut/plasma-cut edges or water jet cutting

Note 1 to entry: The thickness does not exceed one-seventh of the width

3.5.10

sheet

flat-rolled product of rectangular cross-section with uniform thickness over 0,20 mm and up to 4,75 mm inclusive, supplied in straight lengths (i.e., flat) usually with sheared or sawn edges or water jet cutting.

Note 1 to entry: The thickness does not exceed one-tenth of the width.

3.5.11

strip

flat-rolled product of rectangular cross-section with uniform thickness equal to and over 0,2 mm, supplied in coils usually with slit edges

Note 1 to entry: The thickness does not exceed one-tenth of the width.

Note 2 to entry: Corrugated, embossed (with patterns, e.g. grooves, ribs, checkers, tears, buttons, lozenges), coated, edge conditioned and perforated products derived from strip are classified as strip.

Note 3 to entry: In some English-speaking countries,"strip" is called"coiled sheet".

3.5.12

foil

flat-rolled product of rectangular cross-section with uniform thickness equal to or under 0,20 mm

3.5.13

forging stock

hot-worked intermediate solid wrought product, for example rod/bar or billets, or any other cross-section, suitable for forging

Note 1 to entry: Forging stock can be used as casting stock.

3.5.14

casting stock

cast or hot-worked intermediate solid wrought product suitable for casting purposes

Note 1 to entry: Casting includes investment casting, sand casting, rammed graphite casting, permanent mould casting, pressure die casting as well as centrifuged casting.

3.5.15

forging

wrought product formed by hammering or pressing, usually when hot, between open dies (hand forging) or closed dies (drop or die forging)

3.5.16

blank

piece of titanium of regular or irregular shape taken from a flat wrought product intended for subsequent processing such as bending, stamping or deep drawing

3.5.17

circle

circular blank

3.6.1

casting

general term for products at or near the finished shape, formed by solidifying titanium or titanium alloys in a mould

3.6.2

sand/graphite casting

rammed graphite moulding

casting formed in a sand or graphite mould.

3.6.3

permanent mould casting

chill casting

casting formed in a metal mould ここで, the molten metal is introduced by gravity or a low-pressure feed

3.6.4

pressure die casting

die casting

casting formed in a metal mould ここで, the molten metal is introduced under high pressure

3.6.5

centrifugal casting

casting formed by centrifugal force in a rotating mould ここで, the major axis of the casting coincides with the axis of rotation, and the thickness of the casting is determined by the dimensions of the mould and amount of titanium poured

Note 1 to entry: Centrifugal casting is not to be confused with casting under centrifugal pressure.

3.6.6

investment casting

casting method using a ceramic mould formed by wax pattern which is removed before pouring molten titanium and titanium alloys in an inert atmosphere

3.6.7

skull melting technique

technique where the molten metal is contained in a water-cooled copper crucible while confined in vacuum or inert gas chamber

Note 1 to entry: The reactive liquid titanium is prevented from dissolving the crucible due to a solid frozen titanium skull.

Note 2 to entry: Vacuum arc skull melting (VASM) and induction skull melting (ISM)are typical examples of skull melting technology applied to titanium and titanium alloys. These processes involve melting the metal within its own skull using an electric arc or induction coil, which is carried out in a vacuum or under an inert gas environment.

3.6.8

hot isostatic pressing

HIP

post-moulding process to densify castings under temperatures and pressures in an inert atmosphere

Note 1 to entry: Hot isostatic pressing can also be applied to the powder metallurgy process to consolidate and solidify powder.

3.7.1

α-β processing

hot working and annealing in a temperature field below the β-transus temperature, usually the final hot working temperature range

3.7.2

annealing

thermal treatment to soften metal by recrystallization or recovery

3.7.3

ageing

precipitation heat treatment

thermal treatment of an alloy at above room temperature for strengthening by phase transformation and precipitation

3.7.4

β processing

hot working and annealing in a temperature field above the β-transus temperature

3.7.5

bright annealing

thermal treatment in an inert atmosphere for titanium and titanium alloys to prevent scaling or oxidation during annealing

3.7.6

cold working

plastic deformation of titanium and titanium alloys at, for example, room temperature

3.7.7

descaling

procedure to remove the layer of oxide formed on the surface during heating

Note 1 to entry: Shot blasting with steel grit or sand is used for thick-walled cross-sections. A molten salt bath containing an aqueous solution is used for thin-walled pieces, and especially for coils.

3.7.8

diffusion soaking

process in which a metal or an alloy is heated for a period at high temperature, in particular to eliminate or relieve chemical micro-segregation by diffusion

3.7.9

homogenizing

process in which a metal or an alloy is heated for a period at a high temperature, in particular to make the structure uniform at a controlled level

3.7.10

hot working

plastic deformation of titanium and titanium alloys at high temperatures, for example over 700 °C

3.7.11

pickling

procedure to remove α case in an aqueous solution

Note 1 to entry: Prevention against hydrogen pick-up is necessary.

3.7.12

quenching

process of cooling a metal or alloy through contact with a solid, liquid or gas at a rate rapid enough to retain one or all of the soluble constituents in solid solution

Note 1 to entry: Common media used are water, oil or a similar product, or accelerated air.

3.7.13

skin passing

final light cold rolling pass on polished rolls to give a bright finish on coils of titanium and titanium alloys with a controlled influence on the mechanical properties

3.7.14

solution heat treatment

process in which an alloy is heated to a suitable temperature and is held at this temperature long enough to allow soluble constituents to enter into solid solution where they are retained in a super-saturated state upon quenching

3.7.15

solution heat treatment and ageing

STA

heat treatment that includes heating to a temperature at which a solid solution of the alloying elements is formed, then cooling at a rate that maintains this state, followed by precipitation heat treatment

Note 1 to entry: This process increases strength.

3.7.16

stabilising

thermal treatment used to promote stability under service conditions in, for example, dimensions, mechanical properties, structure or internal stress

3.7.17

strain hardening

modification of a titanium structure by cold working, resulting in an increase in strength and hardness, generally with some loss of ductility

3.7.18

stress relieving

annealing method for reducing internal stress by moderate temperatures and controlled smooth cooling

3.7.19

stretch levelling

procedure for smoothing the features of coils by stretching and bending titanium and titanium alloys with a controlled influence to the mechanical properties

3.7.20

superplastic forming

SPF

near-net shape forming method using superplasticity, which is confirmed in several practical alloys with ultra-fine grain microstructure such as Ti-6Al-4V at a high temperature and low strain rate

Note 1 to entry: During tensile testing at a given temperature and low strain rate, the elongation values of these alloys can reach several hundred percent.

3.7.21

diffusion bonding

solid joining process at high temperature, often combined with superplastic forming in order to produce complex components

3.7.22

upset forging

process of swelling the cross section of an ingot or a billet in the α, β or α-β field to control the conversion ratio

3.7.23

additive manufacturing

method to produce 3D objects by stacking layers of melted powder using a high energy beam such as a laser or an electron beam

3.8.1

α case

oxygen-enriched α phase-stabilised surface layer resulting from elevated-temperature exposure

Note 1 to entry: Because α case has high hardness with poor ductility, α case is commonly removed by pickling or mechanical means.

3.8.2

surface finish

surface condition of final products

Note 1 to entry: The typical finishing surfaces are pickled dull surface, vacuum-annealed bright surface and/or shot-blasted surface, ground surface or machined surface.

3.8.3

surface treatment

processing of surfaces to give products special properties

3.9.1

commercial applications

use in such fields as chemical industry, vehicle and consumer, except use in aerospace and military

3.9.2

non-aerospace applications

use in fields other than the aircraft and space-related equipment fields

3.10.1

classification

categorization of titanium materials classified into unalloyed titanium and titanium alloy

Note 1 to entry: For further details, see Annex A.

3.10.2

unalloyed titanium

materials containing a minimum percentage by mass fraction of 98,5 % of titanium with such interstitial elements as carbon, oxygen, nitrogen and hydrogen, and other elements such as iron

Note 1 to entry: Iron is inevitably mixed in due to the use of iron containers during refining and melting.

Note 2 to entry: Other elements other than iron and interstitial elements are not intentionally added and do not exceed the specific limits, unless otherwise specified.

Note 3 to entry: Unalloyed titanium includes high-purity titanium with a purity of N3 or higher, in addition to unalloyed titanium containing trace amounts of the interstitial elements and other elements defined in 3.10.2.

Note 4 to entry: The specific limits for interstitial elements, iron and other elements shall be in accordance with Table A.1.

Note 5 to entry: Exceptions exist in the case of elements that are added in small quantities to enhance corrosion resistance but that do not substantially enhance mechanical properties. Those elements are, for example, palladium, ruthenium, nickel, molybdenum, cobalt, chromium or mixtures thereof.

Note 6 to entry: The maximum mass fraction of alloying elements added to improve corrosion resistance shall be in accordance with Table A.2. The mass fraction of elements other than those specified in Table A.2 shall not exceed 1 %.

Note 7 to entry: ISO 23515 defines the rules for the designation of unalloyed titanium.

3.10.3

titanium alloys

Note 1 to entry: The specific limits for elements added to improve corrosion resistance shall be in accordance with Table A.2.

Note 2 to entry: ISO 23515 defines the rules for designation of titanium alloys.

3.11.1

commercially pure titanium

CP titanium

unalloyed titanium grades with a minimum percentage by mass fraction of 98,5 % of titanium including interstitial elements. iron and residual elements not exceeding the specified limits

Note 1 to entry: The mass fraction of limits of interstitial elements, iron and other elements for commercial pure titanium shall be in accordance with Table A.1.

Note 2 to entry: Increasing levels of interstitial elements and iron lead to higher strength, but lower ductility.

Note 3 to entry: For types of commercially pure titanium with different interstitial elements and iron contents, see ISO 23515:2022, 4.2 and ISO 23515:2022, Table A.1.

3.11.2

corrosion resistance-enhanced grades of commercial pure titanium

unalloyed titanium with enhanced corrosion resistance obtained by adding low percentages by mass fraction of palladium, ruthenium, nickel, molybdenum, cobalt and chromium, either singly or in combination with mechanical behaviour comparable to commercially pure titanium

3.11.3

commercially applied titanium alloys

titanium alloys with improved properties due to adding appropriate percentage by mass fraction of alloying elements enhancing mechanical properties, deformability, weldability and corrosion resistance.

3.11.4

special grade titanium alloys

highly alloyed titanium alloys for special use, such as military and aerospace equipment

3.11.5

titanium-base intermetallic compounds

compounds (metal-to-metal) formed by more than two metallic elements with an ordered lattice crystal structure

Note 1 to entry: Different crystal structures from the constituent metallic elements and in the atomic bonding, covalent bonding and/or ionic bonding state are added to the basic metallic bonding. Completely different crystal structures and/or properties originate from the conventional alloy (solid solution). TiAl and Ti₃Al are fundamental titanium base intermetallic compounds and show excellent mechanical properties at high temperatures.