A2-70 Stainless Steel Hex Head Bolt (2023)

FAQs

What does A2-70 mean on a bolt? ›

Metric bolts made of 304 stainless steel are marked on the bolt head with A2-70. The A2 represents 304 stainless steel and 70 represents the tensile strength. The tensile strength equals 700 MPA general-purpose stainless steel.

A2 / ASTM-304 Is An 18/8 Stainless Steel : This Designates A Metallurgical Content Of 18% Chromium & 8% Nickel. A Bolt Marked A2-70 Is A 304 Stainless Steel Bolt With A 700 N/mm2 Tensile Strength (See Below Table). The -70 Representing The Tensile Strength Divided By 10.

For example, A2-70 has a tensile strength of 700 Nmm-2 and 450 Nmm-2 proof stress.

A2 grade stainless steel is also often referred to as type 304 or 18/8 - this latter label denotes the fact that A2 grade stainless steel contains approximately 8% nickel and 18% chromium. With a high hardness level and consistent dimensional stability, A2 stainless steel shows good resistance to wear & tear.

A2 vs A4 stainless steel strength

Whereas grade A4 is stronger than grade A2, and its tensile properties are almost similar to alloy steel grade 8.8.

Despite the popular belief, a stainless steel bolt is actually weaker than a grade 8 bolt. In fact, according to the Society of American Engineers (SAE), grade 8 bolts are the strongest and hardest hex bolt you would want to use in constructions or the automotive industry.

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Since its launch in 2014, the BUMAX® Ultra range has proven that it is capable of exceeding tensile strengths of between 1 500 to 1 700 MPa on various applications, with good corrosion resistance and an operating range of between -50 and 400°C.

These are called A2 and A4. A2 is also known as 304, whereas A4 is also known as 316.

Grade A2 (AISI 304) has excellent resistance to atmospheric corrosion, except in severe industrial and marine environments.

Is grade 10.9 stronger than stainless steel? ›

Since the material has resistant to shock, it won't come undone, unlike some stainless steel fasteners. Usually, bolts produced in grade 10.9 are tempered and quenched. Because carbon steel has been tempered and quenched, the resultant high strength bolts grade 10.9, becomes harder and tougher.

A2 stainless steel is often referred to as 304 or 18/8 Stainless. 18/8 actually refers to the amount of chromium and nickel in the alloy – 18% chromium and 8% nickel. A2 (304, 18/8) is an austenitic steel and is non-magnetic.

The A2 format is 420 x 594 mm or 42 x 59.4 cm. In inches, A2 paper has a size of 16.5in x 23.4in. These dimensions mean A2 is normally the perfect choice for calendars, posters and larger format printing.

In fact, due to their low carbon content, many stainless steel alloys cannot be hardened through heat treatment. Therefore, when compared to regular steel, the stainless alloys used in bolts are slightly stronger than an un-hardened (grade 2) steel but significantly weaker than hardened steel fasteners.

A grade 8 bolt is the highest grade SAE bolt. Grade 8 bolts have a minimum tensile strength of 150,000 PSI.

Equivalent materials to A2 tool steels are: AFNOR Z 100 CDV 5. DIN 1.2363. JIS SKD 12.

German-Style Steel

Stainless steel contains chromium. This is what lowers the Rockwell scale rating. The benefit is a knife blade that resists corrosion and rust. Cooks generally agree that German-style, stainless steel knife blades are hardier than Japanese-style blades.

To put it simply, an A2 stainless steel does not rust, but must not come into direct contact with salt. On a boat, it will therefore be used for all the fittings screws or mechanical fasteners. On the other hand, an A4 stainless steel may be in direct contact with the salt and will be used on deck.

Is A2 steel hard to sharpen? ›

A2 steel takes a little more effort to sharpen, but you are rewarded with a more durable edge that lasts longer.

Though some Zinc alloys can be very strong, overall stainless steel is stronger. However, zinc is a heavy element, and when alloyed with other metals it provides better corrosion resistance, stability, dimensional strength and impact strength.

Most stainless steel ordered around the world is Grade 304. It offers the standard corrosion resistance, formability, strength, and easy maintenance for which stainless is known. While 316 comes in second in terms of quantities sold, it offers vastly superior corrosion resistance to chlorides and acids.

Stainless steel screws have an incredibly high tensile strength, measuring between 100,000 and 150,000 tensile pounds per square inch (PSI). Screws made from galvanized steel, on the other hand, have an average of only 62,000 PSI.

A2 Stainless Steel

A2 (304, 18/8, EN 1.4301) is an austenitic steel and is non-magnetic. The chromium provides a corrosion and oxidation resistance, however, it can tarnish. It is immune to foodstuffs, sterilizing solutions, most organic chemicals and dyestuffs, also a wide variety of inorganic chemicals.

303 and 304 Stainless are the most commonly listed grades, the standard grade for stainless fasteners. They are corrosion-resistant and durable.

The a4 material has 16% chromium, 2% molybdenum and 10.5% nickel in the composition. The a2 material has 10.5% chromium in the composition. The a4 material has much corrosion resistance than the a2 material. The a4 grade material is used in marine grade applications mostly due to the higher corrosion resistance.

A2 is a 5% Chromium steel which provides high hardness after heat treatment with good dimensional stability. It is heat treatable and will offer a hardness in the range 57-62 HRC.

A2 steel bar is available in a several forms, including square, round, and rectangular. This highly versatile material can be used for a wide variety of tools that require wear resistance, such as industrial hammers, knives, slitters, punches, tool holders, and woodworking cutting tools.

As you may have noticed, the grades of stainless steel are divided into three categories: Austenitic, Ferritic and Martensitic. This classification depends on their structure and composition. The three types will have differing levels of the elements carbon, chromium and nickel.

What is best grade of stainless steel for saltwater? ›

SAE 316 stainless steel is a molybdenum-alloyed steel and the second most common austenitic stainless steel (after grade 304). It is the preferred steel for use in marine environments because of its greater resistance to pitting corrosion than most other grades of steel without molybdenum.

316 grade steel is often known as Marine Grade Stainless Steel and is one of the most common stainless steel on the market. It is an austenitic grade that has also 2-3% molybdenum, further enhancing corrosion resistance.

Type 316 steel or marine grade stainless steel is an austenitic chromium-nickel stainless steel somewhere in the range of two and a 3% molybdenum. The molybdenum content increases corrosion resistance, improves protection from pitting in chloride particle arrangements, and builds quality at high temperatures.

All grades of stainless steel resist corrosion, but grade 304 is particularly rustproof because of its high nickel content. This addition to the alloy makes grade 304 considerably more expensive than grade 430 stainless steel, however.

Austenitic stainless steels generally provide the most corrosion resistance because of their high amounts of chromium. This makes grade 304 an excellent choice when corrosion resistance is important.

High Strength

The highest tensile strengths are seen in the martensitic (431) and precipitation hardening grades (17-4 PH). These grades can have strengths double that of TYPES 304 and 316, the most commonly used stainless steels.

A2 – 420 mm X 594 mm – 42m x 59.4cm – 15.52 inch x 23.39 inch -1:1.41.

Those dimensions are the following: A4 = 216 x 279mm (8.5 x 11 inches) A3 = 279mm x 432mm (11 x 17 inches) A2 = 432 x 559mm (17 x 22 inches)

This gives us an A2 size of 420mm x 594mm. You will notice that this is exactly the same size as 2 A3 sheets or 4 A4 sheets.

Is A1 twice A2 size? ›

The A Series paper size chart, below left, gives a visual representation of how the sizes relate to each other - for example A5 is half of A4 size paper and A2 is half of A1 size paper.

An A2 piece of paper measures 420 × 594 mm or 16.5 × 23.4 inches. Cutting it in half will create two A3 sheets of paper.

A2 stainless steel is often referred to as 304 or 18/8 Stainless. 18/8 actually refers to the amount of chromium and nickel in the alloy – 18% chromium and 8% nickel. A2 (304, 18/8) is an austenitic steel and is non-magnetic. The chromium provides a corrosion and oxidation resistance, however it can tarnish.

Stainless Steel A4 Vs A2 Strength

The A4 grade has 800MPa minimum tensile strength and 600MPa minimum yield strength. The A2 grade has 700MPa minimum tensile strength and 450MPa minimum yield strength. None of these materials could be heat treated to get more strength.

The “70” denotes the minimum tensile strength to be met by the material (actually the bolt, screw or nut after manufacture). Therefore, A2-70 is an austenitic, acid proof stainless grade (usually 304 material – 304 or 304L) which has been cold worked to provide a minimum tensile strength of 700N/mm² (MPa).

A2 Stainless Steel

A2 (304, 18/8, EN 1.4301) is an austenitic steel and is non-magnetic. The chromium provides a corrosion and oxidation resistance, however, it can tarnish. It is immune to foodstuffs, sterilizing solutions, most organic chemicals and dyestuffs, also a wide variety of inorganic chemicals.

A2 is a 5% Chromium steel which provides high hardness after heat treatment with good dimensional stability. It is heat treatable and will offer a hardness in the range 57-62 HRC.

Despite the popular belief, a stainless steel bolt is actually weaker than a grade 8 bolt. In fact, according to the Society of American Engineers (SAE), grade 8 bolts are the strongest and hardest hex bolt you would want to use in constructions or the automotive industry.

A2 has good toughness, better than many high wear resistance steels. It also offers great ease in grinding and polishing for the knifemaker, and ease in sharpening for the end user.

Hardening Tools made from A2 tool steel may be hardened by placing them in a furnace maintained at a temperature of 1725/1775°F (940/969°C). Let the tools heat naturally to the furnace temperature, soak for 20 minutes plus 5 minutes per inch of thickness and air quench.