Nowadays, in industry, rarely what steel grade will be as popular as steel 3. Without any special properties, it is, however, universally used in large volumes at any enterprise, at least partially associated with the use of metal structures and rolled products. So what's the deal?
Steel 3: GOST
Having become acquainted with the relevant GOST, it is not difficult to find out the ins and outs of this steel grade. However, for your convenience, we slightly rephrase the main provisions of GOST. So, steel 3 is a low-carbon structural steel of ordinary quality. This steel was intended for the manufacture of various products by hot-rolled steel.
In addition, the GOST indicates the correct names of steel grades and, accordingly, their correct interpretation is explained. So, for example, steel 3 of interest to us, according to GOST, is referred to only as St3, where:
- St - conditional abbreviation of the word "Steel".
- 3 - designation of the number of a certain steel grade.
By the way, in GOST there are seven of them: from zero to six. Each individual room has differences in chemical composition. Also, each steel grade, with the exception of zero, is divided into several classes that have their own personal designations. For example, G - denotes manganese and its percentage in the alloy, equal to 0.80-0.15%.
The following three designations indicate the degree of deoxidation of the alloy:
- Kp - boiling;
- Ps - half calm;
- Cn is calm.
Ligature
Considering that for steel 3 basic characteristics are mainly set by adding some alloying chemical elements to its composition, it will not be superfluous to know their exact composition. However, it is worthwhile to understand that, according to GOST, steel 3 was produced in five different variations, differing from each other in ligature, so it makes sense to talk about each of the available:
- St3sp is characterized by a composition of 0.22% carbon, 0.30% silicon and 0.65% manganese.
- St3ps is characterized by a lower silicon content - 0.15%.
- In St3kp, the ligature composition is even poorer in silicon - 0.05% maximum, and manganese - 0.60%.
The fourth and fifth grade, under which steel 3 is produced, enters the market under the designation "G", that is, it differs by an increased, relative to other alloys, fraction of the manganese content in the composition. But the mass fraction of the remaining ligature additives also undergoes changes:
- So in St3Gps steel, the percentage of carbon remains unchanged, the percentage of silicon in the alloy remains in the range of 0.15%, and manganese - up to 1.10%.
- Steel of the St3Gsp grade is characterized by a carbon content in the range of 0.20% and silicon - from 0.30%.
However, in addition to the main ligature composition, minor alloys of chromium, copper and nickel are present in the alloy — 0.30% each, sulfur — 0.005%, nitrogen — 0.10%, and phosphorus — 0.04%.
Steel 3: specifications
As with any other industrial structural steel, grades of steel 3 are not required to be of special hardness, like tool high-carbon alloys. For steel 3, the main positive properties are considered to be:
- Resistance to corrosion.
- Ease of processing material manually and mechanically.
- Unlimited weldability with any of the available types of welding.
- Resistance to various internal defects.
It is these qualities that have allowed 3 to become one of the most sought-after brands to date.