Active Member
|
[China]
Address: Room 1109, Loft Office, Green Land International Plaza, No. 275-8 Guoding East Road, Shanghai 200433, P.R. China. (admin(a)shunitesteel.com)
Contact name:Eric
SHANGHAI UNITE STEEL |
|
|
ASTM A335 GRADE P91 HOT ROLLED ALLOY STEEL SEAMLESS PIPES/TUBES
OVERVIEW
A335/SA335 P91 is a ferritic alloy steel that has very high
strength properties, which do not deteriorate with time, and are
creep resistant. It is also called 9 Cr 1 Mo steel, or chrome moly
pipe, based on its composition.
Compared to its predecessors, the T22 or P22 grade, grade P91
exhibits high strength, enduring temperatures up to 600 °C. The
oxidation temperature limits are also higher allowing elements to
be engineered with less thickness. This contributes to an almost 10
times higher thermal fatigue life and allows engineers to increase
the operating temperature to a higher level, increasing efficiency.
P91 typically allows a wall thickness reduction by at least a
2-to-1 ratio. A wall that is thinner creates lighter hanger loads,
less welding time and uses less filler metal.
These advantages are enabled by this steel’s high amount of
chromium. Grade 91 contains 9% chromium and 1% molybdenum compared
to 2.5% chromium in the next best P22 grade.
APPLICATIONS
A335/SA335 P91 is suitable for bending, flanging (vanstoning), and
similar forming operations and for fusion welding. P91 is most
commonly used in the power industry and petrochemical plants where
fluids and gases are transported at extremely high temperatures and
pressures.
P91’s strength and high temperature endurance makes it ideally
suitable for plants that operate on a cyclic basis - like combined
cycle plants. Also, the reduction in thickness suits HRSG
designers, in an HRSG the temperature head is limited and locating
the coils in the heat transfer path is very critical.
P91 is the correct grade for:
STANDARD SPECIFICATIONS
| Process | Seamless Pipes |
| Shape | Round |
| Technique | Hot Rolled |
| Size Range | 32-1200mm OD |
| Thickness | 3.5-200mm WT |
| Pipe End | Plain / Beveled / Vanished / Plastic Caps |
| Coating | Black / Galvanised / 3LPE / Turned / Peeled / Grinded / Polished / Anti – Corrosion Oil |
| Length | 15 Mtr max Cut to Length available |
| Heat Treatment | Spheroidizing / Full Annealing / Process Annealing / Isothermal Annealing / Normalizing / Quenching / Martempering (Marquenching) / Quench And Tempering / Austempering |
| Application | Oil & Gas / Hydro Carbon Process / Automotive / Boiler, Heat Exchanger / Plumbing, HVAC & Firefighting / Structural / General Engineering / Railways / Sewage & Waterwell |
| Quality Inspection | Third Party inspection is acceptable (SGS, BV etc.) |
TOLERANCE FOR SEAMLESS TUBING
| I.D tolerance (mm) | O.D tolerance (mm) | Straightness (mm) |
| H9-H12 | -/+0.5% | 0.20-0.80 |
Relevant Standard & Grades Equivalency
-ASTM A335 Standard Specification for Seamless Ferritic Alloy Steel Pipe for High -Temperature Service
-EN 10297-1 Seamless Circular Steel Tubes for Mechanical and General Engineering Purpose
-DIN2391 Seamless Precision Steel Tubes
-JIS G3441 Alloy Steel Tubes for Machine Purposes
Chemical Requirements, Composition, %
| Standard | Grade | C | Si | Mn | P | S | Cr | Mo |
| ASTM A335 | P91 | 0.08-0.12 | 0.20-0.50 | 0.30-0.60 | 0.020 max | 0.010 max | 8.00-9.50 | 0.85-1.05 |
Chromium, or chrome, improves high-temperature strength and increases
oxidation resistance. It is virtually irreplaceable in resisting
oxidation at elevated temperatures. Chrome also raises the tensile,
yield and hardness at room temperatures.
Molybdenum increases the strength, elastic limit, resistance to wear, impact
qualities and hardenability. It increases the resistance to
softening, restrains grain growth and makes chromium steel less
susceptible to embrittlement. Moly is also the most effective
additive for increasing high temperature creep strength, or creep
resistance. It also enhances the corrosion resistance of steel and
inhibits pitting.
Also present are smaller quantities of nickel and manganese which increase the hardenability of the steel.
The addition of Vanadium (V) and Columbium/Niobium (Cb/Nb) as well
as the control of Nitrogen (N) greatly Improves Creep Strength.
More important than the alloying elements is the formation of this
alloy steel. The steel is formed by normalizing at 1050 °C, then air cooling
down to 200 °C. It is then tempered by heating to 760 °C. The temperatures and cooling rates produce the microstructure that
results in the high creep strength properties.
Mechanical properties
| Standard | Steel Grade | Yield strength MPa (>=) | Tensile strength MPa (>=) | Elongation % (>=) |
| ASTM A335 | P91 | 415 | 585 | 34 |
PROCESSING
Pipe may be either hot finished or cold drawn with the finishing heat treatment noted below.
Heat Treatment of ASTM A335 P91 alloy steel pipe
Our Services
What we can offer?
-We offer a wide range of steel products in a wide variety of dimensions and executions, according to the common international specifications or customize.
-Machining and heat treatment are available.
-Also, we advise you in choosing the right materials.
Quality Assurance
Below inspection will be done in the production.
(1) ray detection---RT;
(2) ultrasonic testing---UT;
(3) Magnetic Particle Testing-MT;
(4) penetration testing-PT;
(5) eddy current flaw detection-ET
Package
In standard export packing and seaworthy material with hexagon shape bundle, covered with tarpaulin, in containers or in bulk, or upon request
Payment & Delivery
1. Both T/T and L/C will be acceptable
2. Trade Terms: FOB, CIF, CFR
3. The delivery will be in 10-15 days if have stock; For customized items, the delivery will be negotiated by both parties
4. Shipping by sea freight from Shanghai Port (PRC) for Bulk orders, by airfreight or express for samples
Shanghai Unite Steel Trading Co., Ltd
We are committed to integrate engineering steel resources in china and serve the global engineering steel market. Our company has more than 15 years of experience in steel researching, production, managing and sales. And our team mostly are based on and worked in national famous steel enterprise.
In the aspect of resources and information, we have established cooperative and stronger relationship with nearly hundred enterprises, either state-owned or private owned in china.
What’s more, we have built long, deep and close business relationship with dozens of steel company, Sharing and holding equities with several steel enterprises. Because of the close cooperation with steel companies and our pioneering spirit, which can ensure us stay at the top competition, and ensure our customers get what they really want!
Q: Are you a manufacturer or merely a trader?
A: We are group of companies and owned manufacturer
bases and trading company. We specialized in special
steel which include alloy structural steel and carbon steel
and stainless steel, etc. All material are
with high quality and competitive price.
Q: How do you guarantee the quality of your product?
A: Firstly, we can provide the certificates from the third party,
such as TUV, CE, if you need. Secondly, we have a complete set
of inspection system and every process is checked by QC. Quality is
the lifeline of enterprise survival.
Q: Delivery time?
A: We have ready stock for most of material grades in our
warehouse. If the material doesn't have stock, the delivery lead
time is about 5-30 days after receiving your prepayment or
firm order.
Q: What is the payment term?
A: T/T or L/C.
Q: Can we visit your company and factory?
A: Yes, warmly welcome! We can book the hotel for you before you
come to China and arrange our driver to our airport to pick you up
when you come.
