overview of  API steel grade – k55, n80, l80, c90, T95, p110, Q125

API Steel Grade – K55, N80, L80, C90, T95, P110, Q125 seamless Steel Tube API steel grades are standardized specifications for steel used in the production of oil and gas Pipes. These grades are defined by the american petroleum institute (API) and are designed to meet specific requirements for strength, toughness, and corrosion resistance. In this article, we will provide an overview of the most commonly used API steel grades – K55, N80, L80, C90, T95, P110, and Q125. K55 is a low-carbon, high-strength steel grade that is commonly used in oil and gas drilling applications. It has good mechanical properties and excellent resistance to corrosion. K55 is often used in Casing and tubing applications where High strength and corrosion resistance are required. N80 is a medium-carbon, high-strength steel grade that is widely used in oil and gas drilling applications. It has good mechanical properties and excellent resistance to corrosion. N80 is often used in casing and tubing applications where high strength and corrosion resistance are required.

L80 is a medium-carbon, high-strength steel grade that is commonly used in oil and gas drilling applications. It has good mechanical properties and excellent resistance to corrosion. L80 is often used in casing and tubing applications where high strength and corrosion resistance are required.

Labels		Outside diameter (d/mm)	T&C (kg/m)	Wall thickness   (t/mm)	Type of end-finish
1	2				J55/k55	M65	L80/R95	N80-1/Q	C90/T95	P110	Q125
4-1/2	9.50	114.30	14.14	5.21	PS	PS	–	–	–	–	–
	10.50	114.30	15.63	5.69	PSB	PSB	–	–	–	–	–
	11.60	114.30	17.26	6.35	PSLB	PLB	PLB	PLB	PLB	PLB	–
	13.50	114.30	20.09	7.37	–	PLB	PLB	PLB	PLB	PLB	–
	15.10	114.30	22.47	8.56	–	–	–	–	–	PLB	PLB
5	11.50	127.00	17.11	5.59	PS	PS	–	–	–	–	–
	13.00	127.00	19.35	6.43	PSLB	PSLB	–	–	–	–	–
	15.00	127.00	22.32	7.52	PSLB	PLB	SLB	PLB	PLB	PLB
	18.00	127.00	26.79	9.19	–	PLB	SLB	PLB	PLB	PLB	PLB
	21.40	127.00	31.85	11.10	–	PLB	PLB	PLB	PLB	PLB	PLB
	23.20	127.00	34.53	12.14	–	–	PLB	PLB	PLB	PLB	PLB
	24.10	127.00	35.87	12.70	–	–	PLB	PLB	PLB	PLB	PLB
5-1/2	14.00	139.70	20.83	6.20	PS	PS	–	–	–	–	–
	15.50	139.70	23.07	6.98	PSLB	PSLB	–	–	–	–	–
	17.00	139.70	25.30	7.72	PSLB	PLB	PLB	PLB	PLB	PLB	–
	20.00	139.70	29.76	9.17	–	PLB	PLB	PLB	PLB	PLB	–
	23.00	139.70	34.23	10.54	–	PLB	PLB	PLB	PLB	PLB	PLB
	26.80	139.70	39.88	12.70	–	–	–	–	P	–	–
	29.70	139.70	44.20	14.27	–	–	–	–	P	–	–
	32.60	139.70	48.52	15.88	–	–	–	–	P	–	–
	35.30	139.70	52.53	17.45	–	–	–	–	P	–	–
	38.00	139.70	56.55	19.05	–	–	–	–	P	–	–
	40.50	139.70	60.27	20.62	–	–	–	–	P	–	–
	43.10	139.70	64.14	22.22	–	–	–	–	P	–	–
6-5/8	20.00	168.28	29.76	7.32	PSLB	PSLB	–	–	–	–	–
	24.00	168.28	35.72	8.94	PSLB	PLB	PLB	PLB	PLB	PLB	–
	28.00	168.28	41.67	10.59	–	PLB	PLB	PLB	PLB	PLB	–
	32.00	168.28	47.62	12.06	–	–	PLB	PLB	PLB	PLB	PLB
7	17.00	177.80	25.30	5.87	–	–	–	–	–	–	–
	20.00	177.80	29.76	6.91	PS	PS	–	–	–	–	–
	23.00	177.80	34.23	8.05	PSLB	PLB	PLB	PLB	PLB	–	–
	26.00	177.80	38.69	9.19	–	PLB	PLB	PLB	PLB	PLB	–
	29.00	177.80	43.16	10.36	–	PLB	PLB	PLB	PLB	PLB	–
	32.00	177.80	47.62	11.51	–	PLB	PLB	PLB	PLB	PLB	–
	35.00	177.80	52.09	12.65	–	–	PLB	PLB	PLB	PLB	PLB
	38.00	177.80	56.55	13.72	–	–	PLB	PLB	PLB	PLB	PLB
	42.70	177.80	63.55	15.88	–	–	–	–	P	–	–
	46.40	177.80	69.05	17.45	–	–	–	–	P	–	–
	50.10	177.80	74.56	19.05	–	–	–	–	P	–	–
	53.60	177.80	79.77	20.62	–	–	–	–	P	–	–
	57.10	177.80	84.98	22.22	–	–	–	–	P	–	–
7-5/8	24.00	193.68	35.72	7.62	–	–	–	–		–	–
	26.40	193.68	39.29	8.33	PSLB	PSLB	PLB	PLB	PLB	–	–
	29.70	193.68	44.20	9.52	–	PLB	PLB	PLB	PLB	PLB	–
	33.70	193.68	50.15	10.92	–	PLB	PLB	PLB	PLB	PLB	–
	39.00	193.68	58.04	12.70	–	–	PLB	PLB	PLB	PLB	PLB
	42.80	193.68	63.69	14.27	–	–	PLB	PLB	PLB	PLB	PLB
	45.30	193.68	67.42	15.11	–	–	PLB	PLB	PLB	PLB	PLB
	47.10	193.68	70.09	15.88	–	–	PLB	PLB	PLB	PLB	PLB
	51.20	193.68	76.20	17.45	–	–	–	–	P	–	–
	55.30	193.68	82.30	19.05	–	–	–	–	P	–	–
7-3/4	46.10	196.85	68.61	15.11	–	–	P	P	P	P	P
8-5/8	24.00	219.08	35.72	6.71	PS	PS	–	–	–	–	–
	28.00	219.08	41.67	7.72		PS	–	–	–	–	–
	32.00	219.08	47.62	8.94	PSLB	PSLB	–	–	–	–	–
	36.00	219.08	53.58	10.16	PSLB	PSLB	PLB	PLB	PLB	PLB	–
	40.00	219.08	59.53	11.43	–	PLB	PLB	PLB	PLB	PLB	–
	44.00	219.08	65.48	12.70	–	–	PLB	PLB	PLB	PLB	–
	49.00	219.08	72.92	14.15	–	–	PLB	PLB	PLB	PLB	PLB
9-5/8	32.30	244.48	48.07	7.92	–	–	–	–	–	–	–
	36.00	244.48	53.58	8.94	PSLB	PSLB	–	–	–	–	–
	40.00	244.48	59.53	10.03	PSLB	PSLB	PLB	PLB	PLB	–	–
	43.50	244.48	64.74	11.05	–	PLB	PLB	PLB	PLB	PLB	–
	47.00	244.48	69.95	11.99	–	PLB	PLB	PLB	PLB	PLB	PLB
	53.50	244.48	79.62	13.84	–	–	PLB	PLB	PLB	PLB	PLB
	58.40	244.48	86.91	15.11	–	–	PLB	PLB	PLB	PLB	PLB
	59.40	244.48	88.40	15.47	–	–	–	–	P	–	–
	64.90	244.48	96.58	17.07	–	–	–	–	P	–	–
	70.30	244.48	104.62	18.64	–	–	–	–	P	–	–
	75.60	244.48	112.51	20.24	–	–	–	–	P	–	–
10-3/4	32.75	273.05	48.74	7.09	–	–	–	–	–	–	–
	40.50	273.05	60.27	8.89	PSB	PSB	–	–	–	–	–
	45.50	273.05	67.71	10.16	PSB	PSB	–	–	–	–	–
	51.00	273.05	75.90	11.43	PSB	PSB	PSB	PSB	PSB	PSB	–
	55.50	273.05	82.60	12.57	–	PSB	PSB	PSB	PSB	PSB	–
	60.70	273.05	90.33	13.84	–	–	–	–	PSB	PSB	PSB
	65.70	273.05	97.77	15.11	–	–	–	–	PSB	PSB	PSB
	73.20	273.05	108.94	17.07	–	–	–	–	P	–	–
	79.20	273.05	117.87	18.64	–	–	–	–	P	–	–
	85.30	273.05	126.94	20.24	–	–	–	–	P	–	–
11-3/4	42.00	298.45	62.50	8.46	–	–	–	–	–	–	–
	47.00	298.45	69.95	9.53	PSB	PSB	–	–	–	–	–
	54.00	298.45	80.36	11.05	PSB	PSB	–	–	–	–	–
	60.00	298.45	89.29	12.42	PSB	PSB	PSB	PSB	PSB	PSB	PSB
	65.00	298.45	96.73	13.56	–	–	P	P	P	P	P
	71.00	298.45	105.66	14.78	–	–	P	P	P	P	P
13-3/8	48.00	339.72	71.43	8.38	–	–	–	–	–	–	–
	54.50	339.72	81.11	9.65	PSB	PSB	–	–	–	–	–
	61.00	339.72	90.78	10.92	PSB	PSB	–	–	–	–	–
	68.00	339.72	101.20	12.19	PSB	PSB	PSB	PSB	PSB	PSB	–
	72.00	339.72	107.15	13.06	–	–	PSB	PSB	PSB	PSB	PSB
16	65.00	406.40	96.73	9.53	–	–	–	–	–	–	–
	75.00	406.40	111.62	11.13	PSB	PSB	–	–	–	–	–
	84.00	406.40	125.01	12.57	PSB	PSB	–	–	–	–	–
	109.00	406.40	162.21	16.66	P	–	P	P	–	P	P
18-5/8	87.50	473.08	130.22	11.05	PSB	PSB	–	–	–	–	–
20	94.00	508.00	139.89	11.13	PSLB	PSLB	–	–	–	–	–
	106.50	508.00	158.49	12.70	PSLB	PSLB	–	–	–	–	–
	133.00	508.00	197.93	16.13	PSLB	–	–	–	–	–	–

C90 is a medium-carbon, high-strength steel grade that is commonly used in oil and gas drilling applications. It has good