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ASSIGNMENT 1

JOEAL LIM GUAN CHIN

15115

PETROLEUM ENGINEERING 21 OCTOBER 2014

Carbon Steel

Carbon steel is a type of metal alloy formed as a result of combined iron and carbon. There

are four (4) types of carbon steel each with many grades. The four (4) grades can be

explained as below:

  Low Carbon Steel –  Composition of 0.05%-0.25% carbon and up to 0.4% manganese.

Also known as mild steel, it is a low cost material that is easy to shape. While not as

hard as higher-carbon steels, its surface hardness can be increased by carburizing.

  Medium Carbon Steel  –   Composition of 0.29%-0.54% carbon with 0.60%-1.65%

manganese. Medium carbon steel is ductile and strong with good wear properties.

  High Carbon Steel  –   Composition of 0.55%-0.95% carbon with 0.30%-0.90%

manganese. It is very strong and holds shape memory well, making it ideal for springs

and wire.

 

Very High Carbon Steel - Composition of 0.96%-2.1% carbon. Its high carbon

content makes it an extremely strong material, though it is brittle and requires special

handling.

It can be seen that the higher the carbon content, the steel become stronger and harder but at

the same time it reduces the ductility and weldability of the steel.

(A) A106GrB

This is a type of carbon steel pipe where the fluid flows inside such pipe is of high

temperature and pressure. Facilities that use this grade of pipe includes boilers, power plants,

oil and gas refineries and et cetera.

Chemical and Mechanical Properties (S-Seamless Pipe):

(According to Hebei Province Gold Mysterious Pipe Co., Ltd.)

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Table 1: Composition of A106GrB carbon steel pipe

Grade  C≤  Mn P≤  S≤  Si≥  Cr"≤  Cu"≤  Mo"≤  Ni"≤  V"≤ 

A 0.25 0.27-0.93 0.035 0.035 0.10 0.40 0.40 0.15 0.40 0.08

B 0.30 0.29-1.06 0.035 0.035 0.10 0.40 0.40 0.15 0.40 0.08

C 0.35 0.29-1.06 0.035 0.035 0.10 0.40 0.40 0.15 0.40 0.08

*The total composition for these 5 elements shall not exceed 1.00%

Table 2: Mechanical properties of A106GrB carbon steel pipe

Grade Rm Mpa Tensile StrengthMpa

Yield PointElongation Delivery Condition

A≥330  ≥205 

20 Annealed

B ≥415  ≥240  20 Annealed

C ≥485  ≥275  20 Annealed

*annealed- heat treatment that alters chemical and physical properties of a materials to increase its

ductility

Dimensional Tolerances:

Table 3: Dimensional tolerances for carbon steel A106GrB

Pipe Type Pipe Sizes Tolerances

Cold DrawnOD

≤48.3mm  ±0.40mm

≥60.3mm  ±1%mm

WT ±12.5%

(B) API5LX65

This grade of steel is of a higher strength, tough, weldable steel for applications in the oil

and gas industry especially at offshore.

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 Figure 1: Example of grading system of API5LX65

-  The steel pipe mentioned herein is substantially modified from the API 5L, X65 standard.

-  Pipes are fully killed and fine grain steel material.

- 

 NACE MR0175:”Satisfactory” 

-  This steel offers enhanced yield tensile ratio of 0.87 (max) and impact values verified from

as low as -30°C.

-  This grade is also known as L450Q in USC Units.

Chemical composition

Table 4: Chemical composition of enhanced API5LX65 carbon steel pipe with thickness (t) <= 25mm

*All values are maximum unless stated otherwise and in unit of percentage

Mechanical Properties

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Table 5: Mechanical properties of enhanced API5LX65 carbon steel pipe 

Stainless Steel

Stainless steel differs from carbon steel by the amount of chromium present. Unprotected

carbon steel rusts readily when exposed to air and moisture. This iron oxide film (the rust) is

active and accelerates corrosion by forming more iron oxide; and, because of the greater

volume of the iron oxide, this tends to flake and fall away.

Stainless steels contain sufficient chromium to form a passive film of chromium oxide, which

 prevents further surface corrosion by blocking oxygen diffusion to the steel surface and

 blocks corrosion from spreading into the metal's internal structure, and, due to the similar size

of the steel and oxide ions, they bond very strongly and remain attached to the surface.

There are three (3) main types of stainless steel namely; austenitic, ferritic, and martensitic.

They can be identified by their microstructure or predominant crystal phase.

i. 

Austenitic:

Austenitic steels have austenite as their primary phase (face centered cubic crystal). These are

alloys containing chromium and nickel (sometimes manganese and nitrogen), structured

around the Type 302 composition of iron, 18% chromium, and 8% nickel. Austenitic steels

are not hardenable by heat treatment. The most familiar stainless steel is probably Type 304,

sometimes called T304 or simply 304. Type 304 surgical stainless steel is an austenitic steelcontaining 18-20% chromium and 8-10% nickel.

ii.  Ferritic:

Ferritic steels have ferrite (body centered cubic crystal) as their main phase. These steels

contain iron and chromium, based on the Type 430 composition of 17% chromium. Ferritic

steel is less ductile than austenitic steel and is not hardenable by heat treatment.

iii. 

Martensitic:

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The characteristic orthorhombic martensite microstructure was first observed by German

microscopist Adolf Martens around 1890. Martensitic steels are low carbon steels built

around the Type 410 composition of iron, 12% chromium, and 0.12% carbon. They may be

tempered and hardened. Martensite gives steel great hardness, but it also reduces its

toughness and makes it brittle, so few steels are fully hardened.

There are also other grades of stainless steels, such as precipitation-hardened, duplex, and

cast stainless steels. Stainless steel can be produced in a variety of finishes and textures and

can be tinted over a broad spectrum of colors.

(A) SS304

Grade 304 is the standard "18/8" stainless; it is the most versatile and most widely used

stainless steel, available in a wider range of products, forms and finishes than any other. It

has excellent forming and welding characteristics. The balanced austenitic structure of Grade

304 enables it to be severely deep drawn without intermediate annealing, which has made this

grade dominant in the manufacture of drawn stainless parts such as sinks, hollow-ware and

saucepans. For these applications it is common to use special "304DDQ" (Deep Drawing

Quality) variants. Grade 304 is readily brake or roll formed into a variety of components for

applications in the industrial, architectural, and transportation fields. Grade 304 also has

outstanding welding characteristics. Post-weld annealing is not required when welding thin

sections.

Grade 304L, the low carbon version of 304, does not require post-weld annealing and so is

extensively used in heavy gauge components (over about 6mm). Grade 304H with its higher

carbon content finds application at elevated temperatures. The austenitic structure also gives

these grades excellent toughness, even down to cryogenic temperatures.

Chemical Formula

Fe, <0.08% C, 17.5-20% Cr, 8-11% Ni, <2% Mn, <1% Si, <0.045% P, <0.03% S

Composition:

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Table 6: Composition for stainless steel grade 304/304L/304H

Grade C Mn Si P S Cr Mo Ni N

304 min.

max.

-

0.08

-

2.0

-

0.75

-

0.045

-

0.030

18.0

20.0

- 8.0

10.5

-

0.10

304L min.

max.

-

0.030

-

2.0

-

0.75

-

0.045

-

0.030

18.0

20.0

- 8.0

12.0

-

0.10

304H min.

max.

0.04

0.10

-

2.0

-

0.75

-0.045 -

0.030

18.0

20.0

- 8.0

10.5

-

Mechanical Properties:

Table 7: Mechanical properties for stainless steel grade 304/304L/304H

Grade Tensile

Strength

(MPa) min

Yield Strength

0.2% Proof

(MPa) min

Elongation (%

in 50mm) min

Hardness

Rockwell B

(HR B) max

Brinell (HB) max

304 515 205 40 92 201

304L 485 170 40 92 201

304H 515 205 40 92 201

304H also has a requirement for a grain size of ASTM No 7 or coarser.

Physical Properties:

Table 8: Physical properties for stainless steel grade 304/304L/304H

Grade Density(kg/m

3)

ElasticModulus

(GPa)

Mean Coefficient ofThermal Expansion

(μm/m/°C) 

ThermalConductivity

(W/m.K)

SpecificHeat 0-

100°C

(J/kg.K)

ElectricalResistivity

(nΩ.m) 

0-

100°C

0-

315°C

0-538°C at

100°C

at

500°C

304/L/H 8000 193 17.2 17.8 18.4 16.2 21.5 500 720