OCTG include three types of seamless tubes, delivered in quenched and tempered condition:

Oil drilling platform

• Drillpipe – heavy seamless tubes that rotate the drill bit and circulate the drilling fluid. Joints of pipe 30 ft (9m) long are coupled together with tool joints
• Casing pipe is used to line the hole. 
• Tubing – a pipe through which the oil or gas is produced from the wellbore. Tubing joints are generally around 30 ft [9 m] long with a thread  connection on each end.

Oil Country Tubular Good (OTCG) Steel
Grades Low Alloy Grades

Yield strength (ksi)	API Grade Code	% Alloy content						Yield Strength (0,2% proof stress) (N/mm2)	Tensile Strength min (N/mm2)
		C	Mn	Ni	Cr	Mo	Cu
40	H40	0.5	1.5					276-552	410
55	K55	0.5	1.5					379~552	655
75	C75-1	0.5	1.7	0.5	0.5	0.40	0.5	517~620	665
90	C90-1	0.35	1.9	0.9	1.2	0.75		620~724	690
95	T95-1	0.35	1.2	0.9	1.5	0.85		655~758	724
125	Q125	0.35	1	0.9	1.2	0.75		860~1035	930
140		0.3	1		1.6	1.1	0.05	965~1171	1034

Table 1: Chemical composition and strength properties of common low alloy OCTG steels.

Traditionally the grades used for for OCTG applications were carbon manganese steels (up to the 55 ksi strength level) or Mo containing grades up to 0.4% Mo.

In recent years deep well drilling and reservoirs with contaminants causing corrosive attack have created strong demand for higher strength materials resistant to hydrogen embrittlement and sulphide stress cracking (SCC).

Highly tempered martensite has been identified as the structure which is most resistant to SCC at higher strength levels, and 0.75% has been found to be the Mo concentration to obtain the optimum combination of yield strength and resistance to SCC ⁽¹⁾.

This is reflected in the list of Mo containing low alloy API standard grades in Table 1 above. For the 75 ksi strength level 0.4% Mo is sufficient, while each of the the higher strength grades up to 125 ksi show the optimum Mo level of 0.75 or 0.80 % .

For higher strength up to 140 ksi (yield strength 965-1171 MPa) dispersion has been introduced as an additional strengthening mechanism by the addition of niobium (columbium). The according grade at the end of the list in table 1 is a non API specialized grade with 0.05% niobium; the molybdenum range is extended to 1.1%.

Oil Country Tubular Good (OTCG) Steel Grades
Stainless Steels

Yield strength (ksi)	API Grade Code	% Alloy content						Yield Strength (0,2% proof stress) (N/mm2)	Tensile Strength min (N/mm2)
		C	Mn	Ni	Cr	Mo	Cu
9% Chromium Stainless
75	C75-9Cr	0.15	0.6	0.5	9	1	0.25	517~620	665
13% Chromium Stainless
80	L80-13Cr	0.22	16	0.5	13		0.25	552~655	655
95/110		0.04 max	0.6	4	13	1.5
95/111		0.04 max	0.6	5	13	2.5

Table 2: Chemical composition and strength properties of OCTG stainless steels.

For service in oil and gas fields with more aggressive corrosion environments stainless API grades are standardized with 9% Cr, 1% Mo and 13% Cr (without Mo).(Table 2).

For high temperature environments with CO2 and H2S, the non API specialized grades shown in table 2 with improved corrosion and SCC resistance have been developed ⁽²⁾. The reduced C content increases Cr in solid solution, which effectively improves the corrosion resistance. Ni and Mo secure both hot workability and corrosion resistance. In particular the addition of Mo improves the pitting corrosion, thereby eliminating initiation sites for SCC.

Owing to its higher Mo content the 2% Mo grade can be used in lower pH and higher H2S environments.

The core of the IPIC quality policy is to capture the highest level of products and services, thus earning customer satisfaction and trust. In the meanwhile it is aimed at developing the performance by utilizing high quality materials and equipment, managed by a well-trained, highly-skilled workforce. This system is applied in an environment that enhances management pro-activeness as well as employee performance.

Objectives of IPIC quality policy

To apply the requirements of the of the international systems: API Q1 & ISO 9000-2000.

To achieve customers’ trust by the continuous development of quality levels.

To measure quality levels based on satisfying customer requirements.

To maximize efficiency in order to reduce operating costs.

To promote and spread the awareness of employees’ responsibility towards quality, both, individually and collectively.

To pursue the production of non-defective products by applying the latest technologies.

To work towards the target of achieving continuous development of products as well as the Quality Management System (Q.M.S.)

Applicable standards & Certifications

IPIC operations encompass all the specified requirements outlined in:

ISO 9000-2000 – Fundamentals and Vocabulary

ISO 9001-2000 Q.M.S – Requirements

ISO 14000

API Q1 Specification for Quality Programs for Oil & Gas industries

API Product Specification 5L 42nd edition : 2000

API Monogram

ASTM 3.1 & ASTM 3.3
ASME Section IX & V
ASNT-TC-1A
DNV- Det Norske Veritas

Commitment to the safety of our people, our customers and the environment is paramount.

You have an expectation that our business practices will be to industry standards and we feel it is necessary to meet those expectations at every oppportunity.

At Teresolsng, we are constantly reviewing HSE procedures and raising the height of the bar.

Perfection is not a lofty goal, but rather an obtainable standard level of operations that we strive to hit in every job we do.

That way, when you call Teresolsng PIPELINE CONTRACTORS LTD. you know the job will be done right and that the levels of health, safety and environmental protection will meet your expectations.