Frequently Asked Questions

Stainless steel must contain minimum 10.5% chromium.This element forms a nonvisible layer on the surface by combining with free oxygen in the air which prevents corrosion.The addition of alloys such as nickel and molybdenum to high amounts of chromium further increases the resistance of the surface of these stainless materials.

First number defines the ratio of chromium within stainless material such as 18% while the second number defines the ratio of nickel.For example, the number of 10 defines the ratio of 10% nickel.As the ratio values increase, higher corrosion value is achieved. While 18/10 "300" series defines the quality of stainless, the expression of 18/0 denotes that there is no nickel in its content and "400" series defines that it is stainless and that this material does not have corrosion resistance as much as "300" series and that it can hold a magnet.   

Unlike carbon steel materials a red oxide layer does not form on the surface of stainless steel.However, such formations can occur on the surface of stainless and this reveals that certain iron particules contact with the surface and that they have impact on the surface.For this reason, its contact mainly with metals containing aluminum, cooper, and iron shoulde be prevented. 

While, 304 stainless steel contains chromium with ratio of 18% and nickel with ratio of 8%, 316 stainless steel contains chromium with ratio of 16%, nickel with ratio of 10%, and molybdenum with ratio of 2%.Addition of molybdenum improves corrosion resistance against chlorides.

Stainless steel "can hold" magnets.Especially steel materials of 400 series reveal magnetic features as they do not have nickel content(Ferritic character).On the other hand, the 300 series may exhibit magnetization properties when exposed to physical changes and stresses such as cold working and surface treatment(sandblasting).

When the chromium ratio exceeds the ratio of 10.5%, a chromium-oxide layer forms on the material not having oxygen permeability and having resistance against oxidation or corrosion.In order to improve the resistance of this "passive" layer, it should be compensated wit solutions containing nitride acid with ratio of 10% and hydrofluoric acid with ratio of 2%.This process is named as passivization.

Yes, steels of 300 series can be hardened "by being processed" but this application must absolutely include cold process so that the material can be shaped by applying such physical resistance.Tihs process of shaping is based on the principle of change in between forms and measures."Tempering" can eliminate hardening following cold processing or it may not remove it depending on features of the form.Steels of 400 series contain two different types of structures.The primary type of structure is named as ferritic(409,430,434,439) which can absolutely not be hardened by means of tempering.Whereas, the second group is named as "martensitic" (403,410,416,420, & 440 A,B,C) and this group can be hardened by means of heat treatment.

The letter of L which is seen right next to the quality unit of stainless such as 304L denotes that carbon content is maximum 0.03%(Normal ratios can be 0.08% at maximum whereas in certain quality groups this ratio can even become 0.15% on maximum).This feature prevents the formation of carbide on the materila, especially at high temperatures in the welding area, and hence, it ensures that the 10.5% chromium ratio remains in the protective layer, providing a flexible physical character.

While stainless material can be easily scratched, it is not so easy to eliminate the scratches that are formed.While they can be transformed to their original form by means of certain professional applications, it is considered to be more effective to replace refrigerator, dishwashing machine or a fitting element that can be replaced economically.While the scratches can be eliminated with materilas such as mob or Scotch Brite® pads, these materials can not be effective regarding deep scratches that form.

Generally stainless materials are sold by undergoing heat treatment.This process also reveals the definition of tempered or untempered.300 series stainless materials can not hardened by means of heat treatment but they can be hardened by cold processing(such as carbon steel).Tensions that form due to these cold processes are normalized wşth heat treatment.

Yes, stainless material possess perfect features with regards to various temperature parameters at highly extreme points determined according the "quality" of stainless material. Stainless materials can be used at low liquid nitrogen levels.(-196 °C) and high levels of temperatures such as 1000 °C.

AISI American Iron and Steel Institute) is mainly used in defining 300 and 400 series.An example for this could be AISI 304.This institution has also published a manuel for the chemical compositions and mechanical values of stainless materials constituting each quality group.These definitions only denote descriptions and not the characteristics.Relevant features have been published in the form of a book by ASTM(American Consortium for material tests).

Yes, in fact standard quality stainless steel has a flexible structure.During processing, it is difficult to vield products with sensitive features in smooth form..However, in order to eliminate this problem,various producers have developed other materials such as 303 series having similar values but eliminating this flexible feature.

They are cold processed, heat treated, passivated,matt surfaces.They are the expression form of the most used surfaces.They have a gray matte and slightly reflective appearance.

No, it is not required to heat stainless steel materials prior to welding process as they are defined to be austenitic(For example, 300 series).

It defines recleaning process of stainless material surfaces at high speed with materials comprised of small particles.While sand is among most used materials, other granulized materials such as steel particles have taken its place.Due to the danger related with processing phase, it is applied in a controlled manner with an air vacuum unit, protective equipment, and suitable ventilation.