Manufacture and sale of steel plates in various sizes and thicknesses. The thickness of the steel plate is defined as about one millimeter to over 50 millimeters. Thin steel plates are divided into 1.2 to 75.2 mm, medium steel plates from 3 to 7.4 mm, and thick steel plates from 5 to 200 mm. A steel plate is a smooth, flat surface, usually made of steel, rolled from a plate. Tin plates are named according to the type of production they are produced, including:
- American ASTM standard
- Russian goose standard
Sheet steel is used in the construction industry, manufacturing installations and equipment, bridge construction, rebar columns, and other industries. This metal product is divided into various types such as board, rib plate, pickling board, oil plate, color plate, galvanized plate, and so on. Thick plates are mostly used for the manufacture of large pipes and API pipes. Over the past 40 years, there have been many changes in the way oil and gas transmission lines are designed, and there has been an increase in the trend to use thicker pipes that can withstand higher pressures to improve transmission efficiency. For this reason, the need to use more durable steel with high toughness has increased. High resistance and toughness allow for the transfer of larger quantities of oil and gas in a shorter time.
API steel is widely used in shipbuilding and in the construction of thick API gas pipelines for oil and gas transmission lines. These steels are basically carbon-manganese steels with increased strength by adding small amounts of microalloying elements. The specifications for these steels used to construct oil and gas pipelines have been standardized by the American Petroleum Institute. The high yield strength, high toughness, adequate relative elongation and low transformation temperature of these steels are considered to be their positive properties. API Pipe Specifications The plumbing industry has grown significantly over the past 30 years due to advances in materials. The most important issue in oil and gas pipelines is to deliver more flow in the shortest possible time. To meet this requirement, pipeline steel must have high strength and toughness. Pipeline steel is manufactured without seams and is used to transport oil and gas. Pipe or transmission pipe steels are manufactured to API 5L and CSA specifications and are named by minimum yield stress in ksi. In the welding process of these pipes, the plate is first formed into a cylinder, and its longitudinal or spiral seam is welded by one of the resistance welding process, continuous welding, fusion welding and double-sided sub-powder arc welding. Given the growing demand for oil and gas in cities and industries, the effective and efficient transfer from production to consumption requires complex and extensive mechanisms. In addition, the natural gas produced must in many cases travel a long distance to reach the consumption area. Therefore, pipelines are a suitable, economical, and safe way to transport oil and natural gas under high pressure. Particular attention must be paid to the design and production of pipelines, installation and maintenance. The intercity gas transmission system uses large diameter steel pipes (containing 10-15MPa high pressure gas). Under such high working pressures, the structure must be in a condition very conducive to safety and perfection.
In some grades of these steels, small amounts of niobium, aluminum, vanadium and titanium alloying elements are added to increase strength. These grades are called high-strength low-alloy steels. In addition to having minimal electrical resistance, these steels must have excellent weldability and high toughness. One group of these steels used in the construction of oil and gas transmission pipelines and standardized by the American Petroleum Institute (API) are API steels. High strength, adequate weldability, high impact resistance and low soft-brittle fracture transition temperature are the main characteristics of these steels. API trachea introduction Because the natural gas resources that have been discovered so far are located in remote areas, natural gas can only be obtained through pipelines. Therefore, the 21st century energy supply system will require high-strength, low-cost pipes. Iran's known natural gas reserves, equivalent to 176 billion barrels of crude oil. Compared to the country's crude oil reserves of 136 billion barrels, this figure is significant and very important. Iran owns 15.5% of its natural gas and is the world's second largest producer of natural gas after Russia. Recently, API X65 and API X70 steels are used for natural gas transmission steel pipelines in Iran, so it is necessary to master the mechanical properties (toughness, yield strength, tensile strength, etc.), microstructure and other information of these two steels. chemical composition and obtained. In the past 40 years of tube manufacturing technology, traditional hot rolling and normalizing gave way to the thermomechanical process (TMCP) in the mid-70s. By using this technique and by adding niobium and vanadium micro alloy and by reducing the percentage of carbon, a steel of API grade X70 is obtained.
Then, in order to achieve higher grades, in 1980, Japanese researchers adopted a method of rapid cooling after rolling, which improved the microstructure of the steel and reduced the percentage of carbon. The increasing trend in the use of high strength steel is shown in the graph below. High-quality pipes made of certain materials allow us to increase the gas pressure in the pipes and use pipes with a larger diameter and thinner wall thickness for a certain amount of gas transfer. Therefore, high-quality pipelines can reduce gas transmission prices or pipeline costs.The advantages and application of API pipe
- Can be used in long oil, gas and water pipelines due to low cost
- Propagation resistance in the pipeline
- Can be used in acidic systems
Introduction to API standardsAPI standards are standards of the American Petroleum Institute. The purpose of this standard is to provide standardized parameters for oil and gas pipelines. This standard describes parameters related to high-strength steel, such as chemical composition, yield stress, breaking strength, welding conditions, manufacturing process, how to perform mechanical tests, etc. API pipeline type According to the API standard, the steel grades are A25, A, B, X42, X46, X52, X56, X60, X65, X70, X80. PSL1 level supports A25 to X70 level, PSL2 level supports B to X80 level. All API levels are identified by letters and numbers. This number indicates the minimum yield strength for this steel and is based on imperial units. It is important to note that this rule does not include A and B levels.
steel thickness
There are many different kinds of steel products in the market. one of the famous products in the market is a steel bar that comes in many thicknesses and diameters. The product is a steel that compensates for the concrete's low tensile strength, equivalent to thick wire. There are different types of rebar including simple, ribbed and coiled, alloy etc. Each of these categories has its own sub-categories. For example, alloy rebar includes mo40 subgrade rebar, st37 rebar, vcn rebar, etc., and ribbed rebar also includes all types of rebar in various sizes and grades. How to calculate the diameter of rebar? Determining the diameter of rebar is very easy for construction engineers who have used the product for many years and those who are active in the field, but if you are a novice engineer or just entering the industry, it is not possible to determine the diameter intuitively. Identify the rebar, so at the beginning of the work, measure its diameter with equipment and tools to gradually become proficient with visual inspection. Formula for calculating rebar diameter By knowing the weight of the product, its diameter can be obtained. If you have the weight of one meter of rebar, you can get an exact number using the following formula. The weight of one meter of steel bars = (specific gravity)*7850*one meter**4 (d^2*3.14) What tools can be used to calculate the diameter of rebar?
The diameter of this product can be measured with rope or even wire. When you wrap the rope around its circumference, you can measure the circumference of the circle. One of the most accurate tools for measuring the diameter of this product is a caliper. The device resembles a French wrench with a precision ruler on the handle and a knife-shaped edge on the head of the tool for measuring the diameter of a core, grooved rod or the same type of thread. To use this product, first the two concepts of the nominal diameter of each single or ribbed bar must be explained. You can read more about how to measure and related details in our article on caliper measuring tips. The nominal diameter of a simple rebar is indicated in the product identification table and is equal to the diameter of a circle with an area equal to the cross-sectional area of the rebar. The nominal diameter of ribbed bars is divided into three categories according to their type. The breakdown includes the nominal diameter, the background diameter, which does not take into account the tread, and the outer diameter, which only takes into account the tread. For example, ironmaking rebar 16 includes these items. The nominal diameter of the rebar is 16, the base diameter is 15, and the outer diameter is 18.
Calculation of equivalent reinforcement cross-sectionsWhen one size of rebar is finished, is it possible to use another size in the workshop? To do this, you must first consult a structural designer, as each rod has a specific size, length, and lap length, and they also have different yield stresses. So you can only do this if the designer allows it. For example, if we want to equate rebar 20 with rebar 25: If we have 10 gauge 20 bars on the structural drawing, but the bars in the shop are 25 gauge, how do you replace the 20 gauge bars? The cross-sectional area of reinforcing bars on the corresponding drawing = cross-sectional area of reinforcing bars on the drawing * number of reinforcing bars on the drawing
- 10 * 3.14 = 31.4 square centimeters
- 25 Reinforcement cross-section = 4.91 cm2
- 31.4 / 4.91 = 6.4 numbers
So we need about 7 size 25 rods.When on a block beam roof, the beam openings are simple and the anchorage value in the supports is zero, in practice a negative anchorage amount occurs due to the integrity of the concrete slab, this is the 8th bar, 10, 12 and even 14 are placed on the upper part of the concrete slab to neutralize the tension caused of the negative anchors on the upper part of the plate. This operation and execution of the anchor point is called "negative moment". The steel bars used in the beams do not have the capacity to carry the anchors, so in the bulkhead system of the structure, negative anchors are used on the sides for support. Normally, the diameter of the beam rod is 16mm ≥ the diameter of the tie rod ≥ 8mm, and the diameter of the transverse rod is 5mm to 10mm. Rebar diameterThere are several methods of the rebar diameter meter, you can use the method to report the size of the rebar in millimeters, usually the size of each rebar is between 8mm and 50mm, the size of the rebar + the length of the rebar + the diameter of the rebar determines its weight, rebar on any size can be used in various applications such as construction.
It may seem strange, but if you measure the diameter of the rebar, after a while you can start measuring with your knuckles. It should of course be mentioned that this method is used. when one intends to determine the approximate diameter. For example, if you have a lot of measuring experience, you can tell the difference between a 20 mm and a 50 mm diameter. By (determining the ideal size in hardenability) you can choose the right steel for a specific application and thus avoid the use of expensive steel. The ideal diameter is the true standard for measuring and comparing the hardness of different steels. Furthermore, with the ideal diameter, the effect of different cooling environments on the thickness of the hardened shell can be studied. In fact, depending on the critical diameter and the desired ideal diameter, avoid hard and expensive high-alloy steels. On the other hand, if a larger hardened shell thickness is required, suitable alloy steel and a mild cooling environment can be used by using a critical diameter rather than simple carbon steel and a strong cooling environment. For the possibility of cracking or deforming the part, he chose Terry, which eliminates the possibility of cracking and at the same time achieves a hardened thickness. The ideal diameter can be calculated using the chemical composition or using standard tests on steel samples and the results obtained therefrom.