1 Definition:

seamless steel pipes have hollow sections, and are applied to pipes for conveying fluids in quantity, such as pipes for conveying petroleum, natural gas, coal gas, water and some solid materials. Compared with round steel and other solid steel materials, steel pipes have lighter weight at the same bending and twisting strength, belong to economic section steel materials, and are widely used for manufacturing structural parts and mechanical parts, for example, annular parts of oil drill rods, automobile transmission shafts, bicycle frames, steel scaffoldings used in building construction and so on are manufactured by steel pipes, which can improve the material utilizing rate, simplify manufacturing processes and save materials and processing time, and have been widely manufactured by steel pipes.

2 Types:

a. Seamless pipe (GB8162-87) for general structure and mechanical structure

b. Seamless pipe (GB/T3087-1999) for low and medium-pressure boiler

c. Seamless pipe ST45.8/111 (GB5310-95) for high-pressure boiler

d. Seamless pipe (GB/T8163-1999) for conveying fluids

e. Cold-drawn or cold-rolled precision seamless pipe (GB3639-83)

f. Geological drilling steel pipe (YB235-70)

g. Oil drilling steel pipe (YB528-65)

h. Seamless pipe (27SiMn) for hydraulic support

i. Seamless pipe (GB6479-86) for chemical fertilizer

j. Shipbuilding pipe (GB5312-85)

k. Oil cracking pipe (GB9948-88)

l. Various alloy pipes (16Mn, 27SiMn, 15CrMo, 35CrMo, 40CrMo, 12Cr1Mov)

3 Production processes:

a. Main production processes (△main inspection processes) of hot-rolled seamless steel pipes:

Pipe blank preparation and inspection △→pipe blank heating →perforation →pipe rolling →steel pipe reheating →sizing (reducing) →heat treatment △→finished pipe straightening →finishing →inspection △→(lossless, physicochemical, platform frame inspection) →warehousing

b. Main production processes of hot-rolled (drawn) seamless steel pipes:

Blank preparation →acid pickling and lubrication →cold rolling (drawing) →heat treatment →straightening →finishing →inspection

4 Standard /Steel Grade:

API 5L PSL1 PSL2 GR.B,X42,X46,X52,X56,X60,X65,X70,X80

API 5CT J55，K55，ASTM A106/ A53/A500 GR.B

ASTM A252 GR.2,GR.3, AWWAC200,

EN10224 L235,L275,L355, EN10025, EN10217, EN10219,

S235JR/JO/J2,S275JR/JO/J2,S355JR/JO/J2/K2

GB/T8162-2008,GB/T8163-2008,GB/T3087-2008,GB/T5310-2008

GB/T6479-2002,20#,45#,20G,20R,Q345B etc.

5 Length:6-12M

6 Packing:

1)In bundle with strip;

2)First packing by plastic bag then strip;

3)In bulk

4)Client' requirements

7 Delivery:

1)Delivery: Container: 25 tons/container for pipe with usual outer diameter. For 20" container the max length is 5.8m; For 40" container the max length is 11.8m.

2)Bulk carrier: It is no requirements to the length of the pipe. But its booking space time is long.

8 Applications:

1. Architecture: more applications in underground pipeline transportation, groundwater withdrawal during building construction, hot water transmission of boilers, etc.

2. Machining, bearing sleeves, machining of machine parts, etc.

3. Electric: gas transmission and water electricity generation fluid pipelines

4. Antistatic pipes in wind power plants, etc.

9 Produce process

10 The chemical composition and mechanical properties