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rail track screw factory
#1
一,螺纹钉的结构特点和种类
螺纹是一个坚实的外表面或横截面的内表面,一个统一的螺旋凸形。
根据其结构特点和用途可分为三类:
(a)普通螺纹:齿形为三角形,用于连接或固定零件。
根据螺距的共同螺纹分为粗牙螺纹和细牙螺纹两种,细牙螺纹连接强度较高。
(2)传动螺纹:梯形三角形,长方形,锯齿形等齿形
(3)密封螺纹:用于密封连接,主要工作螺纹,锥螺纹和锥管螺纹。
其次,线程的级别:
螺纹配合是螺纹的大小和松动或紧密,配合等级是影响内外螺纹的偏差和公差。
(a) with unified inch thread, the thread has three levels: 1 a, 2 a and 3 a, internal thread has three levels:
1 b, 2 b and 3 b, all of them are clearance fit.
Rating the higher the number, with tight.
In inch thread, the deviation provides only 1 a and 2 a, 3 a grade of zero deviation, and level 1 a and 2 a, deviations are equal.
The smaller the number, the greater the tolerance grade,
1, 1 a and 1 b, very loose tolerance grade, its applicable to internal and external thread tolerance to cooperate.
2, 2 a and 2 b, inch series of mechanical fasteners is the most common thread tolerance grade.
3, 3 a and 3 b, spin and form the tight fit, suitable for tolerance of fasteners, key design for safety.
4, external thread, 1 a and 2 a level have a fit tolerance, aaa.
Level 1 a tolerance of 50% larger than 2 a level of tolerance, 75% larger than aaa, internal threads, 2 b level of tolerance is larger than 2 a tolerance of 30%.
1 b 50% larger than 2 b, 75% larger than level 3 b.
(2) metric thread, thread has three levels: 4 h, 6 h and g, internal thread has three levels: 5 h, 6 h, 7 h.
(Japanese standard thread into Ⅰ, Ⅱ precision, Ⅲ level 3, usually situation as Ⅱ level) in the metric thread, H and H basic deviation is zero.
G the basic deviation of positive, e, f and G the basic deviation of negative.
1, H is internal threads commonly used tolerance zone position, is generally not used as surface coating, or use the extremely thin layer of phosphating.
G position basic deviation for special occasions, such as thicker coating, seldom used in general.
2,g通常用于电镀6-9um薄涂层,如产品拉拔要求为6h螺栓,则电镀前应使用6g公差带。
3,螺纹与最佳组合为H / g,H / H或g / H,螺纹为螺纹,螺母等精制紧固件,推荐使用标准6 H / g进行合作。
标准参考类型表面处理水平的直径原材料
AREMA
ASTM
ANSI
SAEM18
M24黑色氧化物
电镀锌等
4.8
5.6
8.8
10.9低碳钢
中碳钢
合金钢轨轨道螺丝工厂
网址:http://www.railwayfishplate.com/rail-track-spike/
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