Most people have seen stainless steel castings at some point in their lives. They have likely seen cast stainless steel parts used in a wide variety of products, from kitchenware to medical instruments, yet few realize why so many designers prefer stainless steel castings.

One of the most valuable assets of stainless steel castings is its resistance to corrosion. Lower grades of stainless steel castings can withstand corrosion in water environments and basic atmospheric conditions. And higher grades of stainless steel castings can withstand corrosion caused by acid and alkaline solutions.

Stainless steel castings contain several alloying elements that are in line with the specific composition and grade. We can divide stainless steel castings into several general classes: austenitic stainless steel castings, ferritic stainless steel castings, martensitic stainless steel castings, duplex stainless steel castings, and precipitation hardened stainless steel castings. The distinction between each class is based primarily on the predominant phase present in the stainless steel castings as determined by the major alloying elements.

Effects of Alloying Elements on Stainless Steel Castings

1. Manganese: Adding manganese to stainless steel improves hot working properties and boosts toughness, strength, and hardness.

2. Nickel: Nickel can help produce stainless steel castings that are incredibly ductile, corrosion resistant, and tough at both high and low temperatures.

3. Chromium: Stainless steel parts with higher percentages of chromium have a higher resistance to oxidation than parts with lower percentages of this alloying element.

4. Carbon: Carbon, along with iron, is the major alloying element that is used to make stainless steel. It is also used to increase the hardness and strength of the metal.

5. Copper: This alloying element enhances the corrosion resistance and formability of the stainless steel castings. Copper can also be added to decrease work hardening in grades designed for improved machinability.

Choose Stainless Steel Casting for Your Next Project

We can well understand that alloying elements can have major effects on stainless steel castings. Now that you know the effects that common alloying elements have on stainless steel castings, it’s time to determine the best option for your specific needs. TCC Casting is a leading supplier of quality stainless steel investment castings to major companies throughout the world and can provide you with the exact component you are looking for. Contact us to discuss your next project!

What is Duplex Stainless Steel Casting?

Duplex Stainless Steel Casting is the casting process using duplex stainless steel as the material. Duplex stainless steel is called “duplex” because they have a two-phase microstructure consisting of grains of ferritic and austenitic stainless steel. The picture shows the yellow austenitic phase as “islands” surrounded by the blue ferritic phase. When duplex stainless steel is melted it solidifies from the liquid phase to a completely ferritic structure. As the material cools to room temperature, about half of the ferritic grains transform to austenitic grains (“islands”). The result is a microstructure of roughly 50% austenite and 50% ferrite.

Duplex Stainless Steel Casting Grade-2205

Duplex 2205 Stainless Steel is a nitrogen-enhanced duplex used in stainless steel casting process for applications requiring high strength and excellent corrosion resistance. It is designed to combine improved resistance to stress corrosion cracking, pitting and crevice corrosion. Duplex 2205 provides nearly double the corrosion resistance typical in other austenitic stainless steels.

Chemical Composition of Duplex Stainless Steel 2205

C	Mn	Si	P	S	Cr	Mo	Ni	N
0.03 Max	2 Max	1 Max	0.03 Max	0.02Max	22.0-23.0	3.0-3.5	4.5-6.5	0.14-0.20

Features of Duplex Stainless Steel Casting

Strength: Duplex stainless steel castings are about twice as strong as regular austenitic or ferritic stainless steel castings.

Toughness and ductility: Duplex stainless steel castings have significantly better toughness and ductility than ferritic stainless steel castings; however, they do not reach the excellent values of austenitic stainless steel castings.

Corrosion resistance: As with all stainless steels, corrosion resistance depends mostly on the composition of the stainless steel castings. For chloride pitting and crevice corrosion resistance, their chromium, molybdenum and nitrogen content are most important. Duplex stainless steel casting grades have a range of corrosion resistance, similar to the range for austenitic stainless steel castings, i.e from Type 304 or 316 to 6% molybdenum stainless steel castings.

Stress corrosion cracking resistance: Duplex stainless steels show very good stress corrosion cracking resistance, a property they have “inherited” from the ferritic side. Stress corrosion cracking can be a problem under certain circumstances (chlorides, humidity, elevated temperature) for standard austenitic castings such as Types 304 and 316 stainless steel castings.

Cost: Duplex stainless steel castings have lower nickel and molybdenum contents than their austenitic counterparts of similar corrosion resistance. Due to the lower alloying content, duplex stainless steels can be lower in cost, especially in times of high alloy surcharges. Additionally, it may often be possible to reduce the section thickness of duplex stainless steel, due to its increased yield strength compared to austenitic stainless steel. The combination can lead to significant cost and weight savings compared to a solution in austenitic stainless steels.

TCC Casting for Douplex Stainless Steel Castings

TCC Foundry specializes in the customized production of duplex stainless steel castings. Our manufacturing capability of duplex stainless steel casting weight ranges from 1g to 50kgs. The minimum wall thickness is 2mm. We can supply 2205 duplex stainless steel castings for below applications:

• Chemical process vessels, heat exchangers and piping
• Oil field piping and heat exchangers
• Bleach washers, chip pre-steaming vessels and pulp mill digesters
• Flue gas desulfurization equipment
• Food processing equipment

We maintain positive communication with our customers to assure that we fully understand our customers’ requirements and manufacture products with the desired characteristics in the most cost effective manner. If you need duplex stainless steel casting for your project, pls get in touch with us right now!

Gravity die casting replys on gravity other than high pressure to pour aluminum or zinc alloys which makes more simple for cast products. Here are some of its advantages:

• Parts are taken from mold directly, excellent dimensional accuracy.
• Compared with sand casting, the surface finish of gravity die cast parts is better.
• Mechanical properties, especially tensile strength, are superior to those made in sand casting.
• The wall thickness of parts can be bigger than those made by pressure die casting.
• Sand core parts could be allowed to creat hollow sections of the parts.
• The tooling cost is much lower than pressure die casting.
• Due to fewer production steps and a simpler apparatus, gravity die casting allows for shorter production times and quicker turnaround.
• Less defects are found by gravity die casting than sand casting.

Of course, gravity die casting is not omnipotent, there are also some disadvantages as follows:

• The tooling costs are higher than sand casting
• The thinnest possible wall is between 3 mm and 5 mm thick
• Not all the metals could be made in gravity die casting, for precision stainless steel parts, investment casting is preferred.

Overall, gravity die casting is cost effective and offers a host of advantages over other techniques. It is a good casting method for its excellent mechanical properties, tight tolerances and quick production capabilities.

After understanding gravity die casting technique, maybe you will ask if it is cost effective to make parts by gravity die casting process? The answer is that gravity die casting is cost-effective for medium- and high-production runs of products. The cost per unit increases when a low volume of parts is required due to the high initial capital cost of the die itself.

A die is machined from solid steel and, due to the irregular and customized design of each one, it can be quite expensive. The tolerances of the die are typically quite stringent. Furthermore, there is the cost of the alloys, the machine shop setup, lubricant and production time. With high-volume production output, these costs are spread over many units and become increasingly lower. The shape retention and quick heat dissipation of the die make it dependable for repeated use.

For manufacturers requiring a high volume of parts, gravity die casting is one of the best options available. It allows for reliable, repeatable parts that provide consistent quality as well as a broad selection of different metal alloys to choose from. Aluminum gravity die casting is one of the most popular and versatile choices for manufacturers needing strength, conductivity, thin walls, low weight, corrosion resistance and good mechanical properties. It is also a relatively affordable alloy to choose.

Most products made with gravity die casting are aluminum castings and can weigh anywhere from around 1 lb. to well over 100 lbs. Applications of gravity die casting are numerous:

• Automotive parts: Engine components, gearbox cases, componentry for cylinders, electronic equipment and structural equipment
• Lighting: Electronic components for lighting, control panels, fixtures, housing and components
• Defense: Military sectors are in need of reproducible parts for weaponry, surveillance and more
• Medical: Surgical equipment, gearboxes and hospital equipment
• Electronics: Hi-fi equipment, consumer electronics, housing, tools and more

Any inquiry on gravity die casting, pls feel free to send us your drawings!

Related Article:

• Gravity vs. Pressure Die Casting