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 و 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”, “304النحاس” و “304HQ”. ال

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

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

302HQ الفولاذ المقاوم للصدأ 1.4567 نموذج المنتجات النهائية

• Coil – Strip
• Foil: Inquire with Ulbrich Stainless Steel Wire – Profile
• دائري
• Flat
• مربع

Applications for 302HQ الفولاذ المقاوم للصدأ

• معدات تجهيز الأغذية
• 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
• Heat exchangers
• Woven or welded screens
• Threaded fasteners
• Springs

هquivalents of grade 302HQ

درجة	UNS No	Old British		Euronorm		Swedish SS	Japanese JIS
		بكالوريوس	En	لا	اسم
302HQ	S30430	394S17	–	1.4567	X3CrNiCu18-9-4	–	SUS XM7

تعبير ranges for 302HQ grade of stainless steel

الخصائص الميكانيكية 

Property	Value
قوة الشد, دقيقة	515 الآلام والكروب الذهنية
قوة الغلة (0.2% دليل), دقيقة	205 الآلام والكروب الذهنية
Elongation in 50 مم, دقيقة	40%
صلابة, الأعلى	201 HB

الخصائص الفيزيائية

درجة	كثافة (kg/m3)	Elastic Modulus (المعدل التراكمي)	Mean Coefficient of Thermal Expansion (µm/m/°C)			توصيل حراري (W/m.K)		حرارة نوعية 0-100 درجة مئوية (J/kg.K)	المقاومة الكهربائية (nΩ.m)
			0-100 درجة مئوية	0-315 درجة مئوية	0-538 درجة مئوية	at 100 درجة مئوية	at 500 درجة مئوية
302HQ	8027	193	17.2	17.8	18.8	16.3	21.5	500	720

المقاومة للتآكل

Equal to or exceeding that of درجة 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.

Heat Resistance

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.

المعالجة الحرارية

Solution Treatment (التلدين) – 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.

اللحام

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.

آلية

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