Tag Archives: stainless steel

Stainless Steel Faucet

Stainless Steel: What You Need to Know

If you saw our recent Tuesday Tip on the differences between stainless steel and aluminum foodservice equipment and supplies, then you’re already a little familiar with a few of the classifications of stainless steel. I wanted to take an opportunity to expand upon these classifications (five in all) and overview a few areas from series to gauges you are likely to come across when researching stainless steel equipment.

Stainless Steel Classifications

1. Austenitic

Austenitic stainless steel is a very common type as it’s one of the most weldable. It’s used for a plethora of industrial and consumer applications, and can be divided into three groups: chromium-nickel (300 series), manganese-chromium-nickel-nitrogen (200 series), and specialty alloys.

2. Ferritic

Another common type of stainless steel, ferritic steel is comprised of iron-chromium alloys. Qualities include good conductibility and formability. Some common types of ferritic steel include 409 and 405 series used in mufflers, kitchen counter and sinks, exhaust systems, etc.

3. Martensitic

Martensitic steels include series 403, 410 and 420. This steel is similar to ferritic steel, but contains more of a balance of Chromium and Nitrogen.

4. Duplex

Duplex steel has a microstructure of equal amounts of ferritic and austenitic steel and usually contains around 25% chromium and 5% nickel. Duplex steel has a high yield strength and a greater resistance to corrosion cracking, and is primarily used in chemical plants and piping applications.

5. Precipitation Hardening

This type of stainless steel is characterized by it’s ability to be hardened by a solution and aging heat treatment. These are comprised of chromium and nickel.

Stainless Steel Gauges

The gauge is the thickness of the stainless steel. The lower the number of the gauge, the thicker and more durable the stainless steel. Common types of gauges are 18, 16, and 14. A 14 gauge worktable is much less susceptible to denting than an 18 gauge table.

The gauge of many types of stainless steel equipment and supplies, most notably stainless steel flatware, will include two numbers and may read something like 18/10, 18/8, or 18/0. This refers to the percentages of chromium and nickel, respectively, in the stainless steel alloy. Unlike how the lowest gauge is thicker than the higher gauges, the higher the nickel percentage has greater resistance to rust and corrosion.

Common Stainless Steel Series

The series of stainless steel relates to the the classification of stainless steel listed above. Some common types of series you are likely to come across include 200 series, 300 series, and 400 series.

200 Series

200 series stainless steel contains 16-18% chromium, 3.5-5.5% nickel, 5.5-7.5% manganese, as well as smaller doses of sulfur, carbon, phosphorous, and nitrogen. 200 series usually refers to austenitic stainless steel, and is used in a variety of applications such as automotive parts, clamps, cookware, food service equipment, kitchen utensils, sinks, etc.

300 Series

16-18% chromium, 6-8% nickel. 300 series is also an austenitic classification of stainless steel, offering good levels of conductibility and high strength with solid corrosion and oxidation resistance. It’s used in a variety of industrial products.

400 Series

10.5-11.7% chromium and varying, but relatively low, degrees of nickel, carbon, manganese, silicon, sulfur, phosphorus and nitrogen. Contains titanium. Designed primarily for the automotive industry, in particular exhaust systems.

Have anything to add? Let us know in the comments!

You may also enjoy our blog on types of applications for stainless steel equipment.

Stainless Steel or Aluminum?

Tuesday Tip: Should You Use Stainless Steel or Aluminum?

Stainless steel and aluminum are two construction materials frequently used in the design of foodservice equipment and supplies, and is usually a big selling point for manufacturers and customers alike. So which one is better? Well, that depends on your needs!

Stainless Steel

Stainless Steel Work Table

Stainless Steel Work Table, CRP model 671-740

Stainless steel is composed of iron, chromium, nickel, manganese and copper. Don’t let the name fool you though. Stainless steel can still stain. A scratch to the surface can lead to rust, as well has heated water that leaves behind deposits and chlorides. However, the reason it is called stainless steel is because it won’t corrode or rust as easily as ordinary steel.

There are five different classifications of stainless steel: austenitic, ferritic, martensitic, duplex, and precipitation hardening. The most popular you’re likely to encounter when shopping for foodservice equipment and supplies is austenitic, ferritic, and martensitic stainless steel.

Austenitic stainless steels are one of the most weldable stainless steels and encompass the common 300 series (chromium-nickel combination), the 200 series (manganese-chromium-nickel-nitrogen combination), and specialty alloys.

Ferritic stainless steel contains iron-chromium alloys. They have high flexibility, but poor temperature strengths when compared to austenitic grades. This is a popular choice manufacturers use when designing kitchen sinks and counters.

Martensitic was the first to be developed for commercial uses, and in the initial stages it was mostly used for produce cutlery. It’s similar to the ferritic group, but contains a balance of chromium and nickel. Combined with the ferritic group, you have your 400 series.

Aluminum

Aluminum Stock Pot

Aluminum Stock Pot, CRP model 535-156

One of the biggest benefits of an aluminum construction is that the material is light-weight and durable. This makes it a great option for structural parts and equipment housings, as well as heavy gauge cookware. It’s also a great conductor of heat. It’s an excellent thermal conductor.

Aluminum has higher oxidation and corrosion resistance because of passivisation, the process of rendering a metal surface chemically inactive.

So, stainless steel or aluminum? Which should you get?

Depends on your use. Aluminum is typically cheaper than stainless steel as stainless steels are harder and usually more difficult to form than aluminum.  However, aluminum has a better thermal conductivity which is better for cooking equipment.

Aluminum is more prone to surface scratches and more likely to dent, so this may be more challenging to clean.

If you’d like more information on the differences between stainless steel and aluminum, check out this blog.

Cookware guide

Choosing Cookware: Which Material is Right for Your Kitchen?

In the kitchen, it’s important to have the right type of cookware to fit your kitchen needs. However, there are so many choices out there, it can be a struggle to understand which material works best for you. With some help from our vendor partner Vollrath, here is a look at a few different types of cookware, and the benefits they bring to the table.

AluminumCookware guide

Aluminum cookware can be used on both gas and electric surfaces. Aluminum is a porous metal, which means it is very responsive to temperature changes, heating up or cooling down quickly. According to Vollrath’s construction materials guide, this type of cookware is lightweight, but may be susceptible to warping and denting. Aluminum cookware is highly reactive to acidic foods, which may alter the flavor and color of some foods. Aluminum is more affordable, and can be cleaned with low alkaline detergents. Find aluminum cookware here.

Stainless SteelCookware Guide

Stainless steel is a non-porous metal. It heats and cools slower and more unevenly than aluminum. However, stainless steel is a great option because it is a non-reactive surface, thus providing flavor neutrality. Also, stainless steel will not pit from the use of heavily acidic foods. According to Vollrath, many chefs feel like they can release more of the caramelized fat on the bottom of a pan back into the sauce they are preparing, which makes the sauce more flavorful. It is recommended to wash stainless steel pans by hand in hot, soapy water. You can find stainless steel pans here.

Cast IronCookware guide

When you talk heavy duty, look no further. Cast iron pans conduct heat more slowly than stainless steel. However, they maintain heat well. Vollrath states it is a favorite for braising or stewing meats. Cast iron must be hand washed and dried thoroughly to prevent rust, and it requires constant seasoning to create a non-stick surface on the pan. Seasoning is done by applying oil or fat to the pan and heating through to bond the fat to the metal. The biggest benefit of cast iron is that if it is taken care of and seasoned properly, the cookware can last almost a lifetime. Find cast iron pans here.

Carbon SteelCookware Guide

Carbon steel cookware is designed for high heat applications. It is thinner and lighter than cast iron, and transmits heat quickly. It is a ferrous metal, so it works well with induction cooking. Carbon steel cookware can typically be used in an oven or under a broiler. Like cast iron, however, carbon steel pans need to be seasoned. Find carbon steel pans here.

Clad CookwareCookware Guide

Clad cookware combines the advantages of stainless steel with that of aluminum. Typically, clad cookware is made of aluminum sandwiched by a stainless steel interior for flavor protection, and a layer of stainless steel on the outside for induction capabilities. There are two types of cookware: fully clad and clad bottom. Vollrath says that fully clad cookware spreads the heat evenly at the bottom and up the side walls. Clad bottom heats primarily at the base of the pan. Both types need to be washed by hand in hot, soapy water.

Find Cookware at Central

You can find all of these types of cookware and more at Central Restaurant Products. Click here to see our full offering.

Stainless Steel vs. Aluminum: Which is Better?

Stainless steel and aluminum are two metals very important to the foodservice industry.  So which is better? Both, actually.  Each metal is better for different applications.  When we attended Vollrath University in late June, they broke the two down and explained which is better for specific uses.

Stainless Steel

Introduction

Stainless steel is made up of iron, chromium, nickel, manganese and copper.  This iron alloy has a minimum of 10.5 percent chromium, an agent that provides corrosion resistance.  It’s non-porous and non-corrosive with a higher resistance to rust as well.

What makes stainless steel less corrosive is a “passive” layer of chromium oxide that the chromium forms.

Vollrath explained this is 12 to 30 percent chromium and too thin to be visible but protects the metal beneath.  Nickel assists in the process and restores itself with oxygen. So—as long as the passive layer or film stays intact, isn’t broken or contaminated, a product remains stainless.

Can it still stain though? Yes. A scratch to the surface can lead to rust.  So can heated water that leaves deposits and chlorides found in salt, water, cleaner and quaternary salts.  But even though the possibility to stain is there, Vollrath reminded us it’s called stainless because it won’t rust, corrode or rust as easily as ordinary steel.

Types of Stainless Steel

There have been at least 150 grades of stainless steel found; 15 of those are used in the foodservice industry and four of those 15 are more popular among foodservice equipment and supplies.

Vollrath explained there are two types of stainless steels:

Austenitic

Comprised of alloy with nickel and chromium.  There are the 200 and 300 series stainless steels and are the most specified grades in foodservice.  Austenitic stainless steels are corrosion and water resistant.  They are non-magnetic as well.

200 series: In general, this type of stainless steel is commonly used for wheel covers and door hardware.  Being more specific to the foodservice industry, these are commonly found in counters, oven parts, covers and tray slides.

300 series: These are typically found in steam table pans, sinks, food processing equipment and Bain Maries.  The 300 series contains 301 and 304 stainless steels.

  • 301 stainless steel is 17 percent chromium and 6 percent nickel (otherwise known as 17/6).  As there is less nickel, it isn’t as corrosion resistant as 304, however Vollrath said it is more difficult to form and is stronger because it has less nickel.
  • 304 stainless steel is 18 percent chromium and 8 percent nickel (otherwise known as 18/8). It resists most oxidizing acids and is very corrosion resistant.

Ferritic

This type of stainless steel does not contain nickel and does not have the same corrosion resistance found in the 200 and 300 stainless steels. It’s also magnetic.

400 series: In general, type 430 stainless steel (explained more in detail below) is found in automotive trim, architecture and mufflers.  Specific to the foodservice industry, this type is common in flatware, carts, structural parts and steam tables.

  • 430 stainless steel is 16 to 18 percent chromium and contains no nickel (otherwise known as 16/18-0).  Despite not having any nickel, it is quite corrosion resistant but not as much as the 300 series.

Aluminum

Introduction

Vollrath explained aluminum has higher oxidation and corrosion resistance because of passivisation.  When aluminum is oxidized, its surface will turn white and will sometimes pit in some extreme acidic or base environments.

Aluminum is more lightweight than other metals and is strong.  It’s particularly strong when blended with alloy elements, hence being ideal for structural parts and equipment housings as well as heavy gauge cookware.

Aluminum is also a great conductor of heat. Vollrath said it has excellent thermal conductivity which makes it ideal for cookware and equipment where good heat conductivity is needed. It is also less expensive than stainless steel.

 

 

Types of Aluminum

Similar to stainless steel, there are different types of aluminum, each different for specific foodservice applications.

1100

Vollrath said this type of aluminum is 99 percent pure.  It’s soft, forms easily and can’t withstand tough commercial duty applications or high heat applications without warping.  This type of aluminum also dents and scratches easily.

3003

This type of aluminum is one to 1.5 percent manganese.  It forms easily and items of this type hold up extremely well for normal use, however, may still be too soft for commercial/heavy duty use.

3004

This type of aluminum is one to 1.5 percent manganese and 1 percent magnesium.  It’s more difficult to form than the 1100 or 3003 and Vollrath said is much more impervious to sever use.  It’s tougher and lasts much longer than 3003.  This is a type of aluminum ideal for quality cookware, bake ware and tougher commercial equipment applications.

Recap: Stainless Steel vs. Aluminum…Which is Better?

Vollrath wrapped up this section with the following information to help determine which metal is best for specific applications.

Strength

Stainless steels are harder and are especially harder to form than aluminum.

Thermal Conductivity

Aluminum has a much better thermal conductivity than stainless steel.

Cleaning

Aluminum is more porous and prone to surface scratches and dent, which makes it harder to clean.

Effect of Foods

Stainless steel is less reactive with foods.  Aluminum can react to foods which may affect color and flavor.

Price

Aluminum is typically lower in price than stainless steel.

Gauges

The gauges for each are different.

Thanks again to Vollrath for the great training and information.  Be sure to check out their products on our website, take a look at their website as well as their Facebook, Twitter and YouTube channel.

Flatware Buying Guide

Need help making a purchase? Central has you covered with a library full of buying guides you can conveniently find on our website

Each Tuesday in December we’ll post one of these buying guides.  If you’re looking for something specific, be sure to check out our buying guide page. Also, check back as we will add more upon the release of our 2012 January master catalog.

Understanding Flatware Weights

Medium Weight

  • Lightest weight flatware
  • Most economical
  • Commonly used in high-volume facilities

Heavy Weight

  • Durable and difficult to bend
  • Ideal for most commercial facilities
  • Available in both 18/0 and 18/10

Understanding Stainless Steel Types

18/0 and 18/10 specifications function to illustrate the percentages of chromium and nickel content in stainless steel. Chromium increases product hardness, while nickel helps resist rust and corrosion. These numbers represent the composition of the stainless steel only, not the weight.

18/0 Patterns

  • Composed of 18% chromium and 0% nickel
  • Value priced
  • Higher shine
  • Can be used with magnetic tableware retrievers and scrap blocks
  • Lower luster

18/10 Patterns

  • Composed of 18% chromium and 10% nickel
  • Maximum protection against corrosion, food and cleaning
  • Soft shine with polished finish that enhances the look of quality
  • Higher luster
  • Durable construction

Estimating How Much Flatware You Need

When estimating the amount of flatware you need, remember to take into account the number of seats in your establishment, the turnover rate, any specialty items on the menu, your warewashing capacity, the type of operation (fine dining, family style, cafeteria, etc.) and your backup inventory requirements.

Based on these factors, Central can help you order the exact amount of flatware you need to be successful.

To determine the right amount of flatware, multiply the number of seats you will be serving with the flatware number listed at the right and divide by 12. This will give you the number in dozens you will need to order.

For more information, view this Flatware Buying Guide in full on our website, which also provides the list of our flatware along with the manufacturer, metal composition, weight and an enhanced image of the handle.

Ready to order? Click here to view our flatware.  And don’t forget to check out all of Central’s buying guides.