302HQ Stainless steel

What is stainless steel 302HQ？

Grade 302HQ is a specialised wire grade with very wide usage for manufacture of stainless steel

fasteners. The inclusion of 3% copper in the composition reduces the cold work hardening rate

substantially compared to Grade 304. 302HQ is standard for manufacture of self-tapping screws

and light machine screws; it is also used for some bolts, set screws, rivets and specialised

fasteners. It has now totally replaced Grades 384 и 305 for cold heading applications, copper

being a lower cost alternative to their high nickel contents.

The designation 302HQ is not standardised – ASTM specifications list the grade as UNS S30430,

and alternative designations for the same grade include «XM-7», «304Cu» и «304HQ». The

standard specification for stainless steel fasteners, Iso 3506, includes 302HQ as an acceptable

composition for fastener grade “A2”; it is commonly produced in strength grades A2-70 and A2-80.

302HQ нержавеющая сталь 1.4567 Форма готовой продукции

• Катушка — Полоска
• Foil: Inquire with Ulbrich Stainless Steel Wire — Profile
• Round
• Flat
• Квадрат

Заявки на 302HQ нержавеющая сталь

• Food processing equipment
• Transport and storage equipment (e.g., beer brewing, milk processing, wine making)
• Kitchen benches, sinks, troughs, equipment, and appliances
• Architectural paneling, railings, and trim
• Chemical containers, including for transport
• Теплообменники
• Woven or welded screens
• Threaded fasteners
• Springs

Эquivalents of grade 302HQ

Оценка	США Нет	Old British		Euronorm		Swedish SS	Japanese JIS
		БС	En	Нет	Имя
302HQ	S30430	394S17	—	1.4567	X3CrNiCu18-9-4	—	SUS XM7

Composition ranges for 302HQ grade of stainless steel

Механические свойства 

Свойство	Ценить
Предел прочности, мин	515 МПа
Предел текучести (0.2% Доказательство), мин	205 МПа
Elongation in 50 мм, мин	40%
Твердость, Макс	201 HB

Физические свойства

Оценка	Плотность (kg/m3)	Модуль упругости (ГПа)	Mean Coefficient of Thermal Expansion (µm/m/°C)			Теплопроводность (W/m.k)		Specific Heat 0-100 °С (J/kg.K)	Электрическое сопротивление (nΩ.m)
			0-100 °С	0-315 °С	0-538 °С	at 100 °С	at 500 °С
302HQ	8027	193	17.2	17.8	18.8	16.3	21.5	500	720

Устойчивость к коррозии

Equal to or exceeding that of Оценка 304. Subject to pitting and crevice corrosion in warm chloride

environments, and to stress corrosion cracking above about 50°C. 302HQ is considered resistant

to potable water with up to about 200mg/L chlorides at ambient temperatures, reducing to about

150mg/L at 60°C.

Теплостойкость

Good oxidation resistance in intermittent service to 870°C and in continuous service to 925°C.

Continuous use of Grade 302HQ in 425-860°C range is usually safe (free of carbide precipitation)

as the grade has a very low carbon content.

Термическая обработка

Solution Treatment (Отжиг) — Heat to 1010-1120°C and cool rapidly. This grade cannot be hardened by thermal treatment.

Cold Work Hardening

302HQ has the lowest work hardening rate of any of the common austenitic stainless steels. This results in a tensile strength increase of approximately 8MPa/%Ra (8MPa increase in tensile strength for each 1% reduction of area of cold work — this data from wire drawing). Even after substantial cold work this grade remains essentially non-responsive to a magnet.

Сварка

Stainless steel AISI 304CU (1.4567, X3CrNiCu18-9) has good weldability and can be used with many common welding processes such as TIG welding and MIG welding. It can also be used for arc welding, but this should be carried out with appropriate welding parameters to avoid overheating and distortion. To reduce tension and maintain the mechanical properties, the material should be allowed to cool in the air after welding. No heat treatment is required.

Обрабатываемость

AISI 304CU (1.4567) stainless steel is generally machinable, but this material hardens during machining. Поэтому, care must be taken to select a sufficient cutting depth. Кроме того, suitable tools and coolants should be used to prevent overheating and extend tool life.