Q1: What is stainless steel?

A: (1)Generally speaking, stainless steel is one kind of steel that is not easy to rust; The root reason is that there is an invisible dense chrome rust -- oxidation film of chrome on the surface , making the metal inside not occur oxidation reaction with air, water and acid (that is the so called rust).

There is much to do between stainless steel and chrome. The element making steel not rust is chrome. There is no stainless steel without chrome. There are other elements like nickel, manganese, silica, Mo in stainless steel. The corrosion resistance is good with the combination of nickel and chrome.

(2) Stainless steel posesses the features of high strength, high lumination and corrosion resistance, and it is widely used in fields like chemical engineering medical, food, aviation and others. According to national rules, stainless steel used for tablewares and kitchen wares should choose 304#(the so-called “18-8”, which include 18% chrome and 8% nickle, with good plasticity and no magnetic.) and 403# (the so-called “18-0”, which include 18% chrome and without any nickle, high plasticity, bad plasticity and magnetic.)

Currently, the usually used materials in most corporates are 201# and 202# (which is chromium manganese nitrogen alloyed steel, mainly to solve the problem of nickel resources shortage, can be used as the substutes for 304#. Usually, stainless steel with little nickle or without nickle can reduce costs.)

Q2: There are “13-0”, “18-0”, “18-8” on stainless steel cookers, what does they mean?

A: The former number represents chrome proportion and the latter one represents nickle proportion.

Q3: Why is some stainless steel magnetic?

A: People use magnet to absorb stainless steel in order to verify true from fake; the one can not be absorbed is fake one while the one cannot be absorbed is true one. Actually, this is a wrong verify method. Stainless steel has various kinds, and it can be divided into the following kinds according to its organization structure in normal temperature:

1. Austenitic: such as 304#, 321#, 316#, 310# and so on;

2. Martensite or ferrite: such as 430#, 420#, 410# and others.

Austenitic is non-magnetic or low magnetic, and martensite or ferrite is magnetic. For composition segragation or improper heat treatment, there may be some martensite or ferrite in austenitic 304#. Thus, 304# stainless steel is low magnetic.

To eliminate the magnetic in 304# steel completely, you should process the steel under high temperature solution treatment to resume the stability.

If stainless steel is non-magnetic or low magnetic, it is 304# steel or 316# steel; if the magnetism is same carbon steel, it is 304# steel.

Q4: Rusty steel is not stainless steel? Steel with magnetism is not stainless steel?

A: To customers, two misunderstandings are as follows:

(1)Rusty steel is not stainless steel. In fact, rustless is relative. If stainless steel product stores salt, sauce, vinegar, soup for a long time, rusty spots will form but won’t corrode inside organization. Just wash and maintain stainless steel product frequently.

(2)Steel with magnetism is not stainless steel. Whether it is magnetic or not cannot be taken as a criterion. It is associated with other metal proportion in iron base alloy. 304#, 201# and 202# steel are non-magnetic while 403# is magnetic, but all of them are stainless steel.