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ASTM A320 Heavy Hex Bolts

Item No.：

A-006

Category：

Hex Bolts

Summary

We passed the ISO9001:2000 quality management system certification in 2019, and organized and trained an elite team of professional production, inspection, sales and distribution.

Tel: +86-574-86520006

E-mail: info@nbasme.com，sales@nbasme.com

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Description

ASTM A320

ASTM A320 is a specification for alloy-steel and stainless steel bolting for low-temperature service. This specification covers alloy steel bolting for pressure vessels, valves, flanges, and fittings for low-temperature service. The bars shall be hot-wrought and may be further processed by centerless grinding or by cold drawing. Austenitic stainless steel may be solution annealed or annealed and strain-hardened. See Specification A962/A962M for the definition of bolting.

The surface treatments supported by our factory are self-color, blackened, Teflon (PTFE), Dacromet-plated, Gumet-plated, hot-dip galvanized and more.

A320 Grade

L7 Alloy Steel	AISI 4140, 4142, 4145 \| Quenched and tempered
L7M Alloy Steel	AISI 4140, 4142, 4145 \| Quenched and tempered
L43 Alloy Steel	AISI 4340 \| Quenched and tempered
B8 Class 1 Stainless steel	AISI 304 \| Carbide solution treated
B8M Class 1 Stainless steel	AISI 316 \| Carbide solution treated
B8 Class 2 Stainless steel	AISI 304 \| Carbide solution treated and strain hardened
B8M Class 2 Stainless steel	AISI 316 \| Carbide solution treated and strain hardened

A320 Mechanical Properties

Grade	Size(in.)	Tempering Temperature °F [°C]	Tensile Strength, ksi [MPa]	Yield Strength, ksi [MPa] (0.2 % offset)	Elongation in 2 in. or 50 mm, %	Reduction of Area, %
Grade	Size(in.)	Min	Min	Min	Min	Min
L7	Up to 2-1/2	1100 [593]	125 [860]	105 [725]	16	50
L7M	Up to 2-1/2	1150 [620]	100 [690]	80 [550]	18	50
L43	Up to 4	1100 [593]	125 [860]	105 [725]	16	50
Class 1: B8, B8C, B8M, B8P, B8F, B8T, B8LN, B8MLN	All	-	75 [515]	30 [205]	30	50
Class 1A: B8A, B8CA, B8MA, B8PA, B8FA, B8TA, B8LNA	All	-	75 [515]	30 [205]	30	50
Class 2: B8, B8C, B8P, B8F, B8T	Up to 3/4	-	125 [860]	100 [690]	12	35
	3/4 - 1	-	115 [795]	80 [550]	15	30
	1 - 1-1/4	-	105 [725]	65 [450]	20	35
	1-1/4 - 1-1/2	-	100 [690]	50 [345]	28	45
Class 2: B8M	Up to 3/4	-	110 [760]	95 [655]	15	45
	3/4 - 1	-	100 [690]	80 [550]	20	45
	1 - 1-1/4	-	95 [655]	65 [450]	25	45
	1-1/4 - 1-1/2	-	90 [620]	50 [345]	30	45

A320 Hardness Requirements

Grade	Hardness Max
L7	321 HBW or 35 HRC
L7M	235 HBW* or 99 HRB
L43	321 HBW or 35 HRC
Class 1: B8, B8C, B8M, B8P, B8F, B8T, B8LN, B8MLN	223 HBW~ or 96 HRB
Class 1A: B8A, B8CA, B8MA, B8PA, B8FA, B8TA, B8LNA	192 HBW or 90 HRB
Class 2: B8, B8C, B8P, B8F, B8T	321 HBW or 35 HRC
Class 2: B8M	321 HBW or 35 HRC

* To meet the tensile requirements, the Brinell hardness shall not be less than 200 HBW or 93 HRB
~ For sizes 3⁄4 in. [20 mm] in diameter and smaller, a maximum hardness of 241 HBW (100 HRB) is permitted

A320 Chemical Requirements (Composition, %)

Element	L7 (AISI 4140)	L43 (AISI 4340)	B8 (AISI 304)	B8M (AISI 316)
Carbon	0.38 - 0.48	0.38 - 0.43	0.08 max	0.08 max
Manganese	0.75 - 1.00	0.60 - 0.85	2.00 max	2.00 max
Phosphorus, max	0.035	0.035	0.045	0.045
Sulfur, max	0.040	0.040	0.030	0.030
Silicon	0.15 - 0.35	0.15 - 0.35	1.00 max	1.00 max
Nickel	-	1.65 - 2.00	8.0 - 11.0	10.0 - 14.0
Chromium	0.80 - 1.10	0.70 - 0.90	18.0 - 20.0	16.0 - 18.0
Molybdenum	0.15 - 0.25	0.20 - 0.30	-	2.00 - 3.00

A320 Recommended Test Temperature for Stock Parts

Grade	Test Temperature
Grade	°F	°C
L7M	-100	-73
L7	-150	-101
L43	-150	-101

A320 Recommended Nuts&Washers

Grade	Nuts	Washers
L7	A194 Grade 4 or 7	F436
L43	A194 Grade 4 or 7	F436
B8 Class 1	A194 Grade 8	SS304
B8M Class 1	A194 Grade 8M	SS316
B8 Class 2	A194 Grade 8	SS304
B8M Class 2	A194 Grade 8M	SS316

About Us

“Treat every dream of life, confidence to oneself, to know that you have the ability to achieve it.” In 2015, the ASME Student Department was established in Ningbo University. Ningbo University is a local university in Ningbo. Ningbo ASME Fasteners arranges graduate job fairs at Ningbo University every year. We hope to promote the development of the fastener industry by introducing outstanding talents. Every year, we will discuss with students about ASME code-related issues. We provide interested students with on-site technical experience sharing in the factory, introduce them to the production process, and let them participate in the practice. It is what our factory can do to produce fastener products in the form of actual production. We hope that more and more young people can provide technical support for the development of basic industries.

FAQ

Q: I would like to know how is the quality of your products, is there any quality guarantee?

A: First of all, our products are sold in many countries around the world like the United States, Europe, the United Arab Emirates, Germany, Japan, South Korea and others. Secondly, the QC department will conduct quality inspections before the products leave the factory, and we can provide third-party organization test reports. Samples are always ready. The quality of our products is guaranteed.

Related Products

ASTM A193 Grade B7 Heavy Hex Bolts

All Thread Rod ASTM Stud Bolt A193 B7 Grade

ASTM A563 A194 F594 Hex Nuts

F436 Hardened Flat Washers

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Address：No. 100, Tianshen Road, Tiangu Industrial Zone, Jiulonghu Town, Zhenhai District, Ningbo, Zhejiang, China.
M.T.：+86-18967865853
TEL：+86-574-86520006
E-mail：info@nbasme.com，sales@nbasme.com

+86-18967865853

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