What is the machinability of 321 stainless steel bar?

What Is 321 Stainless Steel bar ?

321 stainless steel  bar (UNS S32100 / EN 1.4541) is a titanium-stabilized austenitic stainless steel with excellent resistance to intergranular corrosion and high-temperature oxidation. It is widely used in high-temperature piping, exhaust manifolds, heat exchangers, and pressure vessels.

321 alloy bar is essentially Type 304 stainless steel with titanium added, which improves weldability and resistance to carbide precipitation, especially in temperatures between 427°C and 870°C (800–1600°F).

 

 

321 Stainless Steel round bar Machinability and Machining

The machinability of 321 stainless steel is considered moderate to poor, with a relative machinability rating of 45–50% (based on AISI 1212 = 100%).

Nominal speeds and feeds for turning a variety of steels and cast irons with high-speed steel (HSS) single-point and box tools
Material	Hardness, HB	Condition	Depth of cut, mm (in)	High-speed steel tool				Tool material
				Speed		Feed
				m/min	sfm	mm/rev	in./rev	ISO	AISI
Wrought austenitic SS321	135-185	Annealed	1 (0.04)	34	110	0.18	0.007	S4, S5	M2, M3
			4 (0.15)	27	90	0.4	0.015
			8 (0.30)	21	70	0.5	0.02
			16 (0.625)	17	55	0.75	0.03

Nominal speeds and feeds for turning a variety of steels and cast irons with carbide-tipped single-point and box tools
Material	Hardness, HB	Condition	Carbide tool
			Uncoated								Coated
			Speed				Feed		Tool material grade		Speed		Feed		Tool material grade
			Brazed		Indexable
			m/min	sfm	m/min	sfm	mm/rev	in./rev	ISO	C	m/min	sfm	mm/rev	in./rev	ISO	C
Wrought austenitic SS321	135-185	Annealed	105	350	120	400	0.18	0.007	K01, M10	C-3	160	525	0.18	0.007	CK01, CM10	CC-3
			100	325	105	350	0.4	0.015			135	450	0.4	0.015
			76	250	84	275	0.5	0.02		C-2	105	350	0.5	0.02		CC-2
			60	200	64	210	0.75	0.03	K20, M20		–	–	–	–	–	–

Nominal speeds and feeds for turning a variety of steels and cast irons with ceramic tools
Material	Hardness, HB	Condition	Depth of cut, mm (in)	Speed		Feed		Type of ceramic
				m/min	sfm	mm/rev	in./rev
Austenitic SS321	135-185	Annealed	1 (0.040)	425	1400	0.13	0.005	Cold-pressed alumina
			4 (0.150)	275	900	0.25	0.010
			8 (0.300)	185	600	0.40	0.015

Nominal speeds and feeds for turning a variety of steels and cast irons with high-speed steel and carbide cutoff and form tools

Material

Hardness, HB

Condition

Speed

Feed, mm/rev (in./rev)

Tool material grade

Cutoff tool width

Form tool width

m/min

sfm

1.5 mm (0.062 in.)

3 mm (0.125 in.)

6 mm (0.250 in.)

12 mm (0.500 in.)

18 mm (0.750 in.)

25 mm (1.00 in.)

35 mm (1.50 in.)

50 mm (2.00 in.)

ISO

AISI or C

Austenitic SS321

135-185

Annealed

26

85

0.033 (0.0013)

0.041 (0.0016)

0.050 (0.002)

0.050 (0.002)

0.041 (0.0016)

0.036 (0.0014)

0.030 (0.0012)

0.025 (0.001)

S4, S5, K40, M40

M2, M3, C-2

84

275

Speeds and feeds for the deep-hole trepanning of various steels with high-speed tool steels and carbide tools
Material	Hardness, HB	Condition	Speed		Feed		Tool material grade
			m/min	sfm	mm/rev	in./rev	ISO	AISI or C
Austenitic: SS321	135-185	Annealed	20	65	0.075	0.003	S4, S5	M2, M3
			84	275	0.15	0.006	K20	C-2
	225-275	Cold drawn	18	60	0.075	0.003	S4, S5	M2, M3
			69	225	0.10	0.004	K20	C-2

Recommended speeds and feeds for the slab (or plain) milling of ferrous and nonferrous alloys with high-speed steel cutters
Material	Hardness, HB	Condition	Depth of cut, mm (in.)	Speed		Feed per tooth	High-speed steel tool material
				m/min	sfm	mm (in.)	ISO	AISI
Wrought austenitic stainless steel 321	135-185 HB	Annealed	1 (0.040)	55	180	0.15 (0.006)	S4, S2	M2, M7
			4 (0.150)	43	140	0.20 (0.008)
			8 (0.300)	34	110	0.25 (0.010)

Recommended speeds and feeds for the end milling (peripheral) of ferrous and nonferrous alloys with both high-speed steel and carbide cutters
SS321	135-185 HB)	Annealed	diam/2 diam/2	18 (60)	0.025 (0.001)	0.038 (0.0015)	0.075 (0.003)	0.102 (0.004)	S4, S5, S2 (M2, M3, M7)	67 (220)	0.013 (0.0005)	0.025 (0.001)	0.050 (0.002)	0.075 (0.003)	K20, M20 (C-2)

 

Need 321 Stainless Steel Bar with Machining Support?

 

Gnee Stainless Steel is a trusted supplier of 321 stainless steel bars, offering a full range of product forms including:

321 alloy round bars: Diameter from 3 mm to 800 mm

321 flat bars: Thickness 2 mm to 100 mm, width 10 mm to 500 mm

321 hex bars: Across flats from 2 mm to 100 mm

321 stainless steel wire rods and custom extruded profiles

We partner directly with certified steel mills to supply not only 321 stainless, but also high-performance alloys such as SS310S. All products comply with, or exceed, major international quality standards, including ASTM, ASME, SAE, AMS, ISO, DIN, EN, and BS specifications.

with full mill certification (EN 10204 3.1) and optional rough machining or custom CNC cutting.

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