It is mainly used to make high-quality carbon structural steel, alloy structural steel and stainless heat-resistant steel seamless steel pipes for high pressure and above steam boiler pipes.
Mainly used for high pressure and high temperature service of boiler(Superheater tube, reheater tube, air guide tube, main steam tube for high and ultra high pressure boilers). Under the action of high temperature flue gas and water vapor, the tube will oxidize and corrode. It is required that the steel pipe has high durability, high resistance to oxidation and corrosion, and good structural stability.
Grade of high-quality carbon structural steel: 20g、20mng、25mng
Grade of alloy structural steel: 15mog、20mog、12crmog、15crmog、12cr2mog、12crmovg、12cr3movsitib, etc
Grade of rust-resistant heat-resistant steel: 1cr18ni9 1cr18ni11nb
| 牌号 |
质量 等级 |
化学成分(质量分数广小/% |
||||||||||||||
|
C |
Si |
Mn |
P |
S |
Nb |
V |
Ti |
Cr |
Ni |
Cu |
Nd |
Mo |
B |
Als" |
||
|
不大于 |
不小于 |
|||||||||||||||
| Q345 | A |
0.20 |
0.50 |
1.70 |
0.035 | 0.035 |
|
|
|
0.30 |
0.50 |
0.20 |
0.012 |
0.10 |
—— | — |
| B | 0.035 | 0.035 | ||||||||||||||
| C | 0.030 | 0.030 |
0.07 |
0.15 |
0.20 |
0.015 |
||||||||||
| D |
0.18 |
0.030 | 0.025 | |||||||||||||
| E | 0.025 | 0.020 | ||||||||||||||
| Q390 | A |
0.20 |
0.50 |
1.70 |
0.035 | 0.035 |
0.07 |
0.20 |
0.20 |
0.3。 |
0.50 |
0.20 |
0.015 |
0.10 |
— | — |
| B | 0.035 | 0.035 | ||||||||||||||
| C | 0.030 | 0.030 |
0,015 |
|||||||||||||
| D | 0.030 | 0.025 | ||||||||||||||
| E | 0.025 | 0.020 | ||||||||||||||
| Q42O | A |
0.20 |
0.50 |
1.70 |
0.035 | 0.035 |
0.07 |
0.2。 |
0.20 |
0.30 |
0.80 |
0.20 |
0.015 |
0.20 |
—— |
—— |
| B | 0.035 | 0.035 | ||||||||||||||
| C | 0.030 | 0.030 |
0.015 |
|||||||||||||
| D | 0.030 | 0.025 | ||||||||||||||
| E | 0.025 | 0.020 | ||||||||||||||
| Q46O | C |
0.20 |
0.60 |
1.80 |
0.030 | 0.030 |
0.11 |
0.20 |
0.20 |
0.30 |
0.80 |
0.20 |
0.015 |
0.20 |
0.005 |
0.015 |
| D | 0.030 | 0.025 | ||||||||||||||
| E | 0.025 | 0.020 | ||||||||||||||
| Q500 | C |
0J8 |
0.60 |
1.80 |
0.025 | 0.020 |
0.11 |
0.20 |
0.20 |
0.60 |
0.80 |
0.20 |
0.015 |
0.20 |
0.005 |
0.015 |
| D | 0.025 | 0.015 | ||||||||||||||
| E | 0.020 | 0.010 | ||||||||||||||
| Q550 | C |
0.18 |
0.60 |
2.00 |
0.025 | 0,020 | 0.11 |
0.20 |
0.20 |
0.80 |
0.80 |
0.20 |
0.015 |
0.30 |
0.005 |
0.015 |
| D | 0.025 | 0,015 | ||||||||||||||
| E | 0.020 | 0.010 | ||||||||||||||
| Q62O | C |
0.18 |
0.60 |
2.00 |
0.025 | 0.020 |
0.11 |
0.20 |
0.20 |
1.00 |
0.80 |
0.20 |
0.015 |
0.30 |
0.005 |
0.015 |
| D | 0.025 | 0.015 | ||||||||||||||
| E | 0.020 | 0.010 | ||||||||||||||
|
1除Q345A、Q345B牌号外，钢中应至少含有细化晶粒元素Al、Nb、V、Ti中的一种，根据需要，供方可添加其中 一种或几种细化晶粒元素，最大值应符合表中规定。组合加入时，Nb+V+Ti<0.22%° * 对于 Q345、Q390、Q420 和 Q46O 牌号，Mo+Cr<0.30%o °各牌号的Cr、Ni作为残余元素时，Cr、Ni含量应各不大于0.30%；当需要加入时，其含量应符合表中规定或由 供需双方协商确定。 J如供方能保证氮元素含量符合表中规定，可不进行氮含量分析。如果钢中加入Al、Nb、V、Ti等具有固氮作用 的合金元素，氮元素含量不作限制，固氮元素含量应在质量证明书中注明. '当采用全铝时，全铝含量AIt^0.020%B
|
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|
No |
Grade |
Mechanical Property |
||||
|
|
|
Tensile |
Yield |
Extend |
Impect (J) |
Handness |
|
1 |
20G |
410- |
≥ |
24/22% |
40/27 |
— |
|
2 |
20MnG |
415- |
≥ |
22/20% |
40/27 |
— |
|
3 |
25MnG |
485- |
≥ |
20/18% |
40/27 |
— |
|
4 |
15MoG |
450- |
≥ |
22/20% |
40/27 |
— |
|
6 |
12CrMoG |
410- |
≥ |
21/19% |
40/27 |
— |
|
7 |
15CrMoG |
440- |
≥ |
21/19% |
40/27 |
— |
|
8 |
12Cr2MoG |
450- |
≥ |
22/20% |
40/27 |
— |
|
9 |
12Cr1MoVG |
470- |
≥ |
21/19% |
40/27 |
— |
|
10 |
12Cr2MoWVTiB |
540- |
≥ |
18/-% |
40/- |
— |
|
11 |
10Cr9Mo1VNbN |
≥ |
≥ |
20/16% |
40/27 |
≤ |
|
12 |
10Cr9MoW2VNbBN |
≥ |
≥ |
20/16% |
40/27 |
≤ |
Wall Thickness and Outter Diameter:
If there is no special requirements, pipe gonna be delivery as norminal outter diameter and norminal wall thickness. As follow sheet
|
Classification designation |
Method of manufacture |
Size of pipe |
Tolerance |
|||
|
Normal grade |
High grade |
|||||
|
W H |
Hot Rolled（extrude） pipe |
Norminal outter Diameter （D） |
<57 |
士 0.40 |
±0,30 |
|
|
57 〜325 |
SW35 |
±0.75%D |
±0.5%D |
|||
|
S>35 |
±1%D |
±0.75%D |
||||
|
>325 〜6。。 |
+ 1%D or + 5.Take lesser one一2 |
|||||
|
>600 |
+ 1%D or + 7,Take lesser one一2 |
|||||
|
Norminal Wall Thickness （S） |
<4.0 |
±|・丨） |
±0.35 |
|||
|
>4.0-20 |
+ 12.5%S |
±10%S |
||||
|
>20 |
DV219 |
±10%S |
±7.5%S |
|||
|
心219 |
+ 12.5%S -10%S |
土 10%S |
||||
|
W-H |
Thermal expansion pipe |
Norminal outter Diameter
(D) |
all |
±1%D |
±0.75%。 |
| Norminal Wall Thickness
(S) |
all |
+ 20%S -10%S |
+ 15%S -io%s |
||
|
W-C |
Cold drawn(rolled) Ppipe |
Norminal outter Diameter
(D) |
<25.4 |
±'L1j |
— |
|
>25.4 〜4() |
±0.20 |
||||
|
>40 〜50 |
|:0.25 |
— |
|||
|
>50 〜60 |
±0.30 |
||||
|
>60 |
±0.5%D |
||||
|
Norminal Wall Thickness (S) |
<3.0 |
±0.3 |
±0.2 |
||
|
>3.0 |
S |
±7.5%S |
Length:
The usual length of steel pipes is 4 000 mm ~ 12 000 mm. After consultation between the supplier and the buyer, and fill in the contract, it can be delivered steel pipes with a length greater than 12 000 mm or shorter than I 000 mm but not shorter than 3 000 mm; short length The number of steel pipes less than 4,000 mm but not less than 3,000 mm shall not exceed 5% of the total number of steel pipes delivered
Curvature:
The bend per meter of steel pipes shall meet the following requirements:
a) When wall thickness <15 mm, not more than 1.5 rnm / m;
b) 15 mm ＜wall thickness≤ mm, not more than 2.0 mm m;
c) When wall thickness> 30 mm, not more than 3.0 mm / m
Outter diameter≥ 127 mm steel pipe. The same length bend should not be greater than 0.10% of the length of the steel pipe.
According to the requirements of the purchaser, after consultation between the supply and demand parties, and in the contract, it is stated that the bend per meter and full length of the steel pipe may adopt other regulations.
Non-roundness and uneven wall thickness:
According to the requirements of the purchaser, after consultation between the supplier and the purchaser, and in the contract, the roundness and uneven wall thickness of the steel pipe should not exceed 80% of the outer diameter and wall thickness tolerance, respectively.
Delivery weight：
When the steel pipe is delivered according to the nominal outer diameter and nominal wall thickness or the nominal inner diameter and nominal wall thickness, the steel pipe is delivered according to the actual weight. It can also be delivered according to the theoretical weight.
When the steel pipe is delivered according to the nominal outer diameter and minimum wall thickness, the steel pipe is delivered according to the actual weight; the supply and demand parties negotiate. And it is indicated in the contract. The steel pipe can also be delivered according to the theoretical weight.
Weight tolerance：
According to the requirements of the purchaser, after consultation between the supplier and the purchaser, and in the contract, the deviation between the actual weight and the theoretical weight of the delivery steel pipe shall meet the following requirements:
a) Single steel pipe: ± 10%;
b) Each batch of steel pipes with a minimum size of 10 t: ± 7.5%.
In addition to ensuring chemical composition and mechanical properties, hydrostatic tests are performed one by one, and flaring and flattening tests are performed. . In addition, there are certain requirements for the microstructure, grain size, and decarburization layer of the finished steel pipe.