How is the R angle of square tube specified in the international standard?
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 Issue Time
 Dec 15,2022
Summary
This is the R angle, and R is the radius of the angular arc.Generally, the radius of R angle is based on different wall thicknesses. See the following table for the range requirements.
How is the R angle of square tube specified in international standards?
When we purchase and use square tube, the most important point to judge whether the product meets the standard is the value of R angle. How is the R angle of square tube specified in the national standard? I will arrange a table for your reference.
The following is the description of R angle in EN10219 standard
This is the R angle, and R is the radius of the angular arc
Generally, the radius of R angle is based on different wall thicknesses. See the following table for the range requirements. T refers to the thickness
Thickness T

External corner profile C_{1}. C_{2} or R^{a} 

T ≤ 6 6 < T≤ 10 10<T 
1,6T to 2,4T 2,0T to 3,0T 2,4T to 3,6T 

^{a } The sides need not be tangential to the coner arcs. 
Calculation Method of R Angle in Low Temperature Rectangular Tube
The R angle in the cryogenic rectangular tube is the transitional arc at the joint of two planes, which is generally half of the center line of the arc R angle. The value of arc R is generally 1.5~2.0 times of the pipe diameter. The size of R angle is determined according to the wall thickness of lowtemperature rectangular tube. The R angle is divided into inner R angle and outer R angle. The inner R is generally 1.5~2 times of the wall thickness. Square steel pipes with different R angles can also be produced according to user requirements.
For example, for rectangular steel pipe with circular arc R, A=1.0MM, diagonal=1.15MM, how do you know the R angle? If it is a square steel pipe with arc, is the calculation method the same? The rectangle A is wide B, the diagonal C, and the radius R of four corner arcs are equal.
The size of R is required. The formula is as follows: (C/2R) ^ 2=(A/2R) ^ 2+(B/2R) ^ 2C ^ 2/4CR+R ^ 2=A ^ 2/4AR+R ^ 2+B ^ 2/4BR ^ 24 (A+BC) ^ 24 (A ^ 2+B ^ 2C ^ 2)=0 Use the root formula to obtain R.
It should be emphasized here that the R angle of the cryogenic rectangular tube does not refer to the arc, but refers to the center angle. An arc is a segment on the circumference. The included angle between the two ends of the arc and the center of the circle is the center angle. Since the circumference is 2 π R and the corresponding center angle is 2 π, the arc length corresponding to the unit center angle is obtained as 2 π R/2 π=R. Therefore, the arc length corresponding to any central angle a (radian unit)=ar is obtained. The measuring methods and tools for R angle of low temperature rectangular tube include R gauge and projector, R gauge can be used for thick points, projector can be used for fine points, and coordinate measuring instrument can be used for high requirements.
Yuantai's square steel pipe has the precise R angle production capacity, and we can divide it into many types according to the actual use.