1. Description Hollow section is mainly used in steel structure and machinery industry, but normal shape and grade can not satify some special area; So as to match more and more special demand, our company prepare to provide some urgent request hollow as following: 1) special shape like Oval tube, diamond tube, bread tube, special-shaped tube 2）new grade like Q345B, Q345C, Q345D, Q355B, Q355C, Q355D, SS400, 304, 316, 310, 16Mo3, AL-6Xn etc 3) Surface like epoxy primer, shot blasting etc Q345A, Q345B, Q345C, Q345D, Q345E are the distinctions of quality grades, increasing from A to E, mainly due to the difference in impact temperature caused by the content of microelements such as phosphorus and sulfur, which means the impact temperature is different And tube chemical composition mechanical properties. The Q345A grade is no impact; the Q345B grade is a 20 degree shock at room temperature; the Q345C grade is a 0 degree shock; the Q345D grade is a -20 degree shock; the Q345E grade is a -40 degree shock. At different shock temperatures, the value of shock is also different. The Q yield strength is not less than 345Mp. The quality grade indicates the amount of impurity elements (carbon, manganese, silicon, sulfur, phosphorus. It is the impurity element in the steel), and the further A, B, C, and D go, the less the impurity content is. 2. Grade Chemical Composition

Grade	Chemical Composition (%)
	C	Si	Mn	P	S
Q235B	≤0.20	≤0.35	≤1.40	≤0.045	≤0.045
Q345B	≤0.20	≤0.50	≤1.70	≤0.035	≤0.035
Q345C	≤0.20	≤0.50	≤1.70	≤0.035	≤0.030
Q345D	≤0.18	≤0.50	≤1.70	≤0.035	≤0.025

3. Mechanical Property

Grade	Mechanical Property
	Yield Strength (N/mm2)/(Mpa)	Tensile Strength (N/mm2)/(Mpa)	Elongtation (%)
Q235B	≥235	370-500	≥26
Q345B	345	470-630	≥20
Q345C	345	470-630	≥21
Q345D	345	470-630	≥21

4. Surface treatment: Epoxy zinc-rich primer Shot Blasting: 5. Q345 C/D/E application: 1) Q345C seamless pipe is mainly used in mechanical institutions, hydraulic equipment, widely used in chemical, petroleum, textile, medical, food, machinery and other industries, mainly used in industrial corrosion-resistant pipes, structural parts and parts. 2) Q345D seamless steel pipe is mainly used in ships, boilers, pressure vessels, oil storage tanks, bridges, power station equipment, lifting and transportation machinery and other high-load welded structural parts. 3) Q345E cryogenic tubes are used in high pressure and high temperature pipelines and equipment such as power plants, nuclear power plants, high pressure boilers, high temperature superheaters and reheaters. The Q345E cryogenic tube has a hollow section and is widely used as a pipeline for transporting fluids, such as pipelines for transporting oil, natural gas, gas, water and certain solid materials. 6. Other customized Parts: 5. Q345 C/D/E application: Q345D seamless steel pipe, Q345D seamless pipe, Q345D steel pipe, Q345E seamless steel pipe, seamless steel pipe for high pressure fertilizer equipment, low temperature steel pipe for power plants, chemical plants and boilers.