无缝钢管的分类，生产过程和机械性能

According to different production methods, it is divided into hot-rolled pipe, cold-rolled pipe, cold-drawn pipe, extruded pipe, pipe jacking, etc., all of which have their own process regulations. The materials are ordinary and high-quality carbon structural steel (Q215-A~Q275-A and 10~50 steel), low alloy steel (09MnV, 16Mn, etc.), alloy steel, stainless acid-resistant steel, etc. According to the use, it is divided into two categories: general use (for water, gas pipelines and structural parts, mechanical parts) and special (for boilers, geological exploration, bearings, acid resistance, etc.).

Seamless steel pipes are widely used. General-purpose seamless steel pipes are rolled from ordinary carbon structural steel, low-alloy structural steel or alloy structural steel, with the largest output, and are mainly used as pipelines or structural parts for conveying fluids. .2. According to different uses, it is divided into three types of supply: a. According to chemical composition and mechanical properties; b. According to mechanical properties; c. According to hydraulic test. Steel pipes supplied according to categories a and b, if they are used to withstand liquid pressure, shall also be subjected to a hydrostatic test. 3. There are many kinds of seamless pipes for special purposes, such as seamless pipes for boilers, seamless pipes for chemical power, seamless pipes for geological use and seamless pipes for petroleum.

无缝的钢管具有空心截面，被广泛用作运输流体的管道，例如用于运输油，天然气，天然气，水和某些固体材料的管道。与固体钢（例如圆形钢）相比，当弯曲和扭转强度相同时，钢管的重量也更轻，并且是经济的部分钢。

它被广泛用于结构零件和机械零件的制造，例如油管，汽车变速箱，自行车框架和用于建筑中使用的钢脚手架。使用钢管制造环零件可以改善材料利用率，简化制造工艺，节省材料和处理工时已被广泛用于制造钢管。

生产过程

①热卷无缝钢管的主要生产过程（△主要检查过程）：

试管空白制备和检查△→管空置加热→穿孔→管滚动→钢重新加热→固定（还原）直径→热处理→热处理→成品管道伸直→修整→检查△（非损坏，物理和化学物质，台湾检验）→仓库

②冷卷（绘制）无缝钢管的主要生产过程：

钢坯准备→腌制润滑→冷滚动（图）→热处理→拉直→整理→检查

The production process of general seamless steel pipes can be divided into two types: cold-drawing and hot-rolling. The production process of cold-rolled seamless steel pipes is generally more complicated than that of hot rolling. In the sizing test, if the surface does not respond to cracks, the round tube will be cut by a cutting machine and cut into a billet with a length of about one meter. Then enter the annealing process, annealing should be pickled with acidic liquid, and pay attention to whether there is a lot of blistering on the surface during pickling. If there is a lot of blistering, it means that the quality of the steel pipe does not meet the corresponding standard. In appearance, the cold-rolled seamless steel pipe is shorter than the hot-rolled seamless steel pipe. The wall thickness of the cold-rolled seamless steel pipe is generally smaller than that of the hot-rolled seamless steel pipe, but the surface looks brighter than the thick-walled seamless steel pipe, and the surface is not too much. Much rough, and the caliber doesn’t have too many burrs.

The delivery state of hot-rolled seamless steel pipe is generally that the hot-rolled state is delivered after heat treatment. After the quality inspection, the hot-rolled seamless steel pipe must be strictly hand-selected by the staff. After the quality inspection, the surface should be oiled, followed by several cold-drawing experiments, and the perforation experiment should be carried out after the hot-rolling treatment. If the diameter of the perforation is too large, it should be straightened and corrected. After straightening, it is transferred to the flaw detector by the conveyor for flaw detection experiment, and finally labelled and arranged in specifications, and then placed in the warehouse.

圆管空白→加热→刺穿→三旋转器偏斜滚动，连续滚动或挤压→管去除→尺寸→尺寸（或还原）→冷却→矫正→伸直→静水测试（或缺陷检测）→标记→存储无缝的钢管，它是由无缝的钢管制成的。钢锭或实心管通过穿孔制成毛细血管，然后热卷，冷卷或冷。无缝钢管的规格以外径 *壁厚的毫米表示。

热卷的无缝管的外径通常大于32mm，壁厚为2.5-200mm，冷滚动无缝管的外径可达到6mm，壁厚可以达到0.25mm，并且薄薄的 -围墙的管道可以达到5mm。滚动比热滚动具有更高的尺寸精度。

通常，无缝的钢管由10、20、30、35、45和其他高质量的碳钢16MN，5MNV和其他低合金结构钢或40CR，30crmnsi，45MN2，40MNB，40MNB和其他组合的钢热滚动或其他钢热滚动或冷卷。由低碳钢制成的无缝管道（例如10和20）主要用于流体运输管道。45、40CR和其他中碳钢无缝管用于制造机械零件，例如汽车和拖拉机的压力部分。通常，无缝的钢管用于确保强度和扁平测试。热滚水管以热卷或热处理状态输送；冷钢管以热处理状态输送。

顾名思义，热滚动具有滚动片的高温，因此变形电阻很小，并且可以实现大量的变形。以钢板的滚动为例，连续铸造板的厚度通常约为230mm，在粗糙的滚动和整理滚动后，最终厚度为1〜20mm。同时，由于钢板的宽度比较小，尺寸精度要求相对较低，并且板形问题不容易出现，主要控制是控制冠。对于有组织要求的人，通常通过受控的滚动和控制冷却来实现它，即控制打开温度和终点滚动的滚动温度。圆管坯料→加热→穿孔→标题→退火→腌制→上油（铜板）→多通冷图（冷滚动）→钢坯管→热处理→直接处理→直接处理→直接处理→液压测试（缺陷检测）→标记→存储→存储。

机械性能指数

钢的机械性能是确保钢的最终用途特性（机械性能）的重要指标，该特性取决于钢的化学成分和热处理系统。在钢管标准中，根据不同的使用要求，指定了拉伸性能（拉伸强度，屈服强度或屈服点，伸长点），硬度和韧性指示器以及用户所需的高温和低温性能。

①拉伸强度（σb）

在拉伸过程中，样品在断裂时携带的最大力（Fb）除以样品的原始横截面区域（SO）（σ），称为拉伸强度（σb），单位为N/MM2（MPA）。它代表了金属材料在张力下抵抗损害的最大能力。

②Yield point (σs)

对于具有屈服现象的金属材料，试样在不增加拉力（在拉伸过程中保持恒定）而继续拉长的应力称为屈服点。如果力减小，则应区分上和下屈服点。屈服点的单位为N/MM2（MPA）。

上屈服点（σSU）：试样产量之前的最大应力和力首次下降；较低的产率点（σSL）：忽略初始瞬态效应时，产量阶段的最小应力。

裂缝（σ）之后的延长

在拉伸测试中，打破样品后的规格长度的增加百分比称为伸长率。它由σ表示，单位为％。计算公式为：σ=（lh-lo）/l0*100％

④截面收缩（ψ）

In the tensile test, the percentage of the maximum reduction of the cross-sectional area at the reduced diameter of the specimen after the specimen is broken is called the reduction of the area. It is expressed in ψ and the unit is %. Calculated as follows:

⑤Hardness index

金属材料抵抗硬物体凹痕的能力称为硬度。根据不同的测试方法和应用范围，硬度可以分为Brinell硬度，洛克韦尔硬度，维克斯硬度，岸硬度，微硬度和高温硬度。对于管道，有三个常用的硬度：Brinell，Rockwell和Vickers。

1. Brinell Hartness（HB）

使用具有一定直径的钢球或胶结球，用指定的测试力（F）压入样品表面，在指定的保持时间后卸下测试力，并测量表面的压痕直径（L）样本。Brinell硬度值是测试力的商，除以压痕球形的表面积。该单元在HBS（钢球）中表达，为N/MM2（MPA）。

Brinell硬度的测量更准确和可靠，但通常HBS仅适用于低于450N/mm2（MPA）的金属材料，不适用于更硬的钢或更薄的板。在钢管标准标准中，Brinell硬度是最广泛使用的，材料的硬度通常由压痕直径D表示，既直观又方便。

示例：120HBS10/1000/30：指示在1000kgf（9.807KN）的作用下，通过直径为10mm的钢球测量的Brinell硬度值30S（秒）为120N/mm2（MPA）。