advanced high strength steel Archives - Page 4 of 6 - National Material Company

25 11, 2018

The Life Cycle of an Ultra High-Strength Steel

marshall2019-09-12T20:09:19+00:00November 25th, 2018|News Blog, NMC Media|

In recent years, the automotive industry has benefited greatly from the integration of advanced high-strength steels (AHSS).

Each step of the manufacturing process of a new advanced high-strength steel, the different configurations of chemical composition, and achievable microstructures, is a result of a closely controlled heating and cooling process. During these processes, several strengthening mechanisms are employed to achieve different levels of strength, fatigue tolerances, and toughness.

Among the advanced high-strength steel family are Dual Phase (DP), Complex Phase (CP), Transformation-Induced Plasticity (TRIP), Martensitic (MS), and Ferritic-Bainitic (FB). They are all produced by controlling the chemistry and cooling rate in the austenite-ferrite phase during the hot rolled phase or in the annealing furnace.

But, what are the steps that are taken to create each of these materials? What are all the factors that metallurgists are searching for when they undertake such a task?

Here’s a checklist:

Designed for mass production

The driving force behind creating any variant of AHSS is to produce it on a mass scale. Therefore, starting from day one, full-scale processing concerns are addressed in the design. Different compositions are simulated and tested to achieve the most optimal composition.

Forgeability

The materials’ forgeability refers to the total fatigue, fracturing toughness, and tensile strength tolerances of the steel alloy.

Machinability

Tests are rendered on the material to observe its boring, tapping, milling, threading, drilling, and turning capabilities. Everything is tested, from the optimal insert and cutting tool configurations to the best feed speed.

Heat treatment

The material will be tested for the mechanical differences between their annealed and hardened states.

Combination of properties

There are an incredible amount of possible alloying compositions using elements such as cobalt, nickel, manganese, copper, carbon, chromium, and more. Rigorous testing is done on the different alloy compositions to achieve the optimal desired properties.

Strength

What’s the key factor in any structure material? Its functional strength. The ultimate tensile strength (UTS) is the most important aspect of weight-limiting designs, so this property is the among the most crucial in the creation of new AHSS steels.

Fracture toughness

Another important element of the steel is its fracture toughness. This measures the materials’ ability to resist fracturing under stress.

Yield strength

As opposed to fracture toughness, yield strength refers to the point at which the fibers of the material begin to break down, and its form becomes plastic, instead of elastic. A higher yield strength will allow part designs to endure more stress before becoming disfigured.

THE RENEWABILITY OF ADVANCED HIGH-STRENGTH STEEL

Once the material is created and tested for mass production, it begins its life as it is machined into a useable part for the automotive industry. What happens as it’s made, put out into the world, and comes to the end of its life cycle?

Efficient steel production

Though AHSS is, at the moment, more expensive overall to produce than traditional steel grades, it […]

17 10, 2018

Steel Service Center Spotlight: National Blanking

Kelly Smith2020-04-01T21:13:37+00:00October 17th, 2018|News Blog, NMC Media|

National Blanking steel service center is a joint venture between National Material Company and Heidtman Steel Products which have enjoyed the synergy of working together for decades to provide quality products to their customers. Partnering to offer customers first operational blanks, including a strong expertise in high-strength low alloy steels, and Advanced High-Strength Steel.

Originally built in 1959 as Toledo Pickling and Steel Service, the facility operated a batch pickler, numerous slitters, and level lines. Toledo Pickling grew rapidly and outpaced the building, resulting in the purchase of another facility down the road where the first blanking press was installed. Incorporated as Toledo Blank Inc. (TBI) in 1974, the company cultivated a reputation as one of the foremost blankers in the country. TBI’s excellence in blanking continued with its new ownership when New Technology Steel acquired the business in 2003.

That tradition followed and prospered under Heidtman Steel with their acquisition of the facility in 2009. In December 2016, Heidtman and National Material Company grew its partnership with the genesis of the joint venture National Blanking LLC. The newly-structured JV allows National Blanking the opportunity to leverage new resources, to tap a larger, more diversified sales force, and to chart a new course for profitable growth.

“What sets National Blanking apart from our competition is our customer-centric commitment to excellence. We understand our customers’ gold standards in regards to quality, service, and on-time delivery. Every employee strives to exceed those expectations every single day,” says Matt McCaffrey, General Manager of National Blanking and 15-year employee. “My favorite part of working at National Blanking is our people. Most of our staff have been with us for more than a decade which has helped cultivate a true sense of family in our work environment. I couldn’t ask for a better team to work with.”

National Blanking offers a broad range of blanking and steel services covering a wide scope of industries. The facility supports press sizes up to 1200 tons with bed sizes up to 84” x 120”, coils up to 55,500 lbs. and 72” wide, with a gauge range of .020 – .500. Other capabilities include circle blanking utilizing multi-cavity tooling with an expansive selection of diameter components that allow the retrofitting of existing tooling to provide low cost solutions for our customers. Our on-site die shop supports flexible value-added services including blank-through, compound, and progressive blanking.

National Blanking serves the following industries: Tanks & Pressure vessels, Agriculture, Appliance, Automotive, Construction, Drums/Containers, Energy, Filters, Furniture, Heavy Equipment, Heavy Truck, HVAC, Lighting, and more. Steel products made at National Blanking are used in wheels, hot water heaters, compressors, trucks and trailers, and medical equipment.

“We strive to build a culture of employee empowerment. We focus on giving our employees not only the training and skills to perform their jobs, but the opportunity and encouragement to engage in all processes and future opportunities for our company,” McCaffrey continues, “the sky is the limit for us. With our knowledge and experience in the industry, we strive to continue our commitment […]

8 08, 2018

How Metal Manufacturing Supports the Agricultural Industry

Kelly Smith2018-08-08T19:12:21+00:00August 8th, 2018|News Blog, NMC Media|

When you think of farming what’s the first thing that comes to mind? Rows of crops? Animals in a barn? Bails of hay perhaps? All these things are likely be found on farms but what is often forgotten about is the equipment that makes all these elements possible. From feeding pails to tractors to silos, the metal manufacturing industry is intrinsically linked to the agricultural industry. Modern farming is extremely efficient, mostly thanks to the industrialized nature of the facilities filled with factory-like machines. We will explore how the steel industry supports the agriculture and farming industry, the advantages it provides, and how National Material Company is prepared to supply the necessary materials to agricultural OEMS.

How is steel used in the agriculture and farming industry?

The agriculture industry is becoming increasingly competitive because of the efficiency of the operations. With higher quality metals, agricultural machine manufacturers create more reliable, efficient machines that translate into better farming. Steel is found in a variety of farming equipment including:

Storage facilities like barns and silos
Harvesting equipment like tractors, cotton pickers, hay balers, etc.
Greenhouses
Livestock management equipment like fencing, feeding pails, milk machines, etc.
General operation equipment like forklifts, watering systems, drains, etc.

What’s the advantage of using steel in agriculture and farming?

Agriculture and farming is dirty business; filled with heat, dirt, chemicals, and various harsh elements from the great outdoors. This means that farming equipment is susceptible to being easily corroded, creating a demand for tougher, resilient equipment. This is where steel comes in. Hot-dip galvanized steel provides corrosion protection that can often last for decades, even when exposed to the harsh environment of farming.

Stainless steel is also utilized for its surface properties. With a standard, shiny finish, it makes it particularly easy to clean. Also, in applications like dairy farming, the smooth finish is important because of the need to maintain microbiological quality in the raw milk.

What can NMC provide for agricultural and farming equipment companies?

As an increasingly competitive industry, having the best source for metal fabrication is critical for any agricultural OEM. National Material Company is capable of providing a wide variety of metals including galvanized steel and advanced high-strength steel, as well as steel processing like blanking and pickling, to these manufacturers.

Our experienced team can provide an array of materials with good design, maximum corrosion resistance, and do so with accelerated customer service. Whether you’re looking to build small parts for a milking machine, or large sheets of metal for a grain silo, NMC can serve you. With our ISO- 9002 certification, you have reassurance that your farming equipment is produced with the highest quality standards.

About National Material L.P. – Since its founding in 1964, National Material Limited Partnership has grown to over 30 business units and is now one of the largest suppliers of steel in America. The National Material group of industrial businesses consists of the Steel Group, Stainless and Alloys Group, Raw Material Trading Group, Aluminum Group, and Related Operations.

If you believe your company can benefit […]

11 07, 2018

Introduction to Press-Hardened Steels

Kelly Smith2018-07-11T17:06:31+00:00July 11th, 2018|News Blog, NMC Media|

What are Press-Hardened Steels (PHS)?

Press-Hardened Steels are Boron added (.001%-.005%) Carbon /Manganese steels that have been in use since the mid 1980’s for automotive body in white construction.

These steels are also known as HF or Hot Formed Steel.

Press Hardened Steel or Hot Formed Steels undergo a unique manufacturing process where the steel is heated to a minimum temperature of 850*C then formed to a final shape in water cooled dies that control the rates of cooling / quench to insure desired properties are met. The high temperature combined with rapid cooling transforms the microstructure to nearly 100% Martensite and very high finished tensile strengths up to 2000 Mpa. This process is commonly referred to as “Hot Stamping”. The finished product qualifies as advanced high-strength steel, and is three times as stable as the material was prior to undergoing the process. It’s strength-to-weight ratio is also vastly increased.

The implementation of press hardening applications and the utilization of hardened steels are promising alternatives for optimizing part geometries with complex shapes with no spring back issues. The Hot Forming process allows for the formation of shapes that cannot be cold stamped with Ultra High Strength steels.

The unique properties of this material combine both complexity and strength – and components made with press-hardened steel can accomplish in one piece what would usually require heavier, thicker parts that are welded together.

The Press-Hardening / Hot Forming process was first put in to practice in the mid 1980’s and is primarily used in the creation of crash-sensitive safety components in automobiles. The parts created with this process meet several of the evolving requirements of the automobile industry, such as weight and cost reduction, as well as reduced environmental impact in its creation.

Since being introduced, Hot Forming has steadily increased in popularity. Recent model year vehicles have seen the percentage of these steels rise to 25% of body in white weight.

PHS / HF Steels can be supplied with coatings that prevent the formation of oxide during the process. The most common of these coatings is Aluminum Silicon (AS) coating, other coatings may include Hot Dipped (GI), Galvannealed (GA) or Zinc Nickle (GP).

These parts are typically used where part stiffness and low deformation are important, typical parts may include.

A-Pillar
B-Pillar
Front / Rear Side Member
Crossmembers
Door Ring

Properties of Press-Hardened Steels

The strength of press-hardened steels can reach as high as 2000 MPa (215ksi), with a 1000MPa (145 ksi) yield stress total.

The Press Hardening Process

The two different processes for press-hardening are as follows.

Direct, in which the steel is first superheated in a furnace, formed while it is still hot, and then quenched while within the die. The process goes like this:

The steel with a ferritic-pearlitic matrix is austenized in a furnace. The blanks are heated up to a high temperature, nearly reaching 1000*C.
The material is then removed from the furnace and immediately transported to the stamping machinery within 10 seconds of removal
The die is closed, and the part is formed
The die is then rapidly quenched. […]

3 05, 2018

What are TRIP Steels?

Kelly Smith2018-05-11T18:23:52+00:00May 3rd, 2018|News Blog, NMC Media|

WHAT ARE TRIP STEELS (Transformation Induced Plasticity Steels)?

TRIP Steels (Transformation Induced Plasticity Steel) are part of the Advanced High-Strength Steel (AHSS) family.

The microstructure of TRIP steels consists of at least five-volume percent of retained austenite, which is embedded in a primary ferrite matrix. The microstructure also contains hard phases like bainite and martensite in varying amounts.

TRIP steels are notable due to the higher carbon content than other members of the AHSS family, such as dual phase steels. They typically require the use of an isothermal hold at an intermediate temperature, which produces some bainite. Silicon and aluminum are added in order to both accelerate the ferrite and bainite formation process, as well as avoiding carbide buildup in the bainite region of the material.

Greater silicon, aluminum, and carbon content of TRIP steels result in large fractions of retained austenite in the material’s final microstructure. The increased carbon content also stabilizes the retained austenite phase below the usual ambient temperature.

Changing the carbon content helps to control the strain level at which the austenite begins to transform into martensite. At low carbon levels, the transformation of the retained austenite will begin almost immediately upon deformation, which will then improve the formability and work hardening rate during the stamping process.

At higher carbon content, the transformation will occur only at strain levels beyond those utilized during the forming processing. The retained austenite remains after the final stage of the forming process at these higher carbon levels – the transformation into martensite will occur only during subsequent deformation; in the case of automobiles, an example would be a crash event.

PROPERTIES OF TRIP STEELS

TRIP Steels can be produced as hot-rolled, cold-rolled, or hot dip galvanized, with a strength range from 500 MPa to 800 MPa.

TRIP Steels are highly sought after due to their high work hardening rate, which is created by the hard second phases that are dispersed in the soft ferrite during deformation. Despite the fact that initial work hardening rate of the material is lesser than that of, say, dual phase steels, TRIP steels sustain their hardening rate at much higher strain levels, where DP steel’s work hardening rate would deteriorate.

As a result of the high work hardening rates, TRIP steels also have substantial stretch forming properties.

The high strain hardening capacity and mechanical strength make these steels an excellent candidate for automotive parts that require a high energy absorption capacity. TRIP steels also have a strong bake hardening following deformation, which even further improves their crash performance.

To summarize TRIP steel’s properties:

Work hardening – When compared to other advanced high-strength steels, TRIP steels exhibit and retain a higher work hardening rate at higher levels of strain.
Formability – As a byproduct of the high work hardening rate, these steels have substantial stretch forming properties, and can be put through stamping processes in a relatively stable manner.
Bake hardening – TRIP steels have a very high bake hardening capacity, and can by doing so can increase their yield strength by close to 70 MPa.

[…]

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