9Cr18MoV and 90Cr18MoV refer to the same type of steel. 9Cr18MoV is China GB/T 3280-1992’s old standard designation, while 90Cr18MoV is China GB/T 20878-2007’s new standard designation. 9Cr18MoV is an improved version of 9Cr18Mo. The addition of vanadium in 9Cr18MoV significantly improves its wear resistance and edge retention compared to 9Cr18Mo.

High-carbon, high-chromium martensitic stainless steel 9Cr18MoV(90Cr18MoV) is a modified 9Cr18 (95Cr18) steel with added molybdenum and vanadium. Both its hot strength and temper resistance are superior to 9Cr18 (95Cr18) steel. Its performance and applications are similar to 9Cr18 (95Cr18) steel. It is used to manufacture bearings that work in corrosive environments and strong oxidizing atmospheres, such as those in petroleum, chemical, and marine machinery. It is also suitable for making wear-resistant parts, mechanical tools, measuring tools, cutting tools, and surgical instruments. Furthermore, it is well-suited for high-load, high-wear, and corrosion-resistant plastic molds.

1. Chemical Composition(GB/T 20878—2007)

C	Cr	Mo	V	Ni	Si (≤)	Mn (≤)	P (≤)	S (≤)
0.85 ~ 0.95	17.00 ~ 19.00	1.00 ~ 1.30	0.072 ~ 0.12	-0.6	0.8	0.8	0.04	0.03

Equivalent Grade and compositions

Padrão	Grau de aço	C	Cr	Mo	V	Ni	Si (≤)	Mn (≤)	P (≤)	S (≤)
Japan JIS	SUS440B	0.75 ~ 0.95	16.00 ~ 18.00	≤(0.75)	-	-0.6	1	1	0.04	0.03
EUA ASTM	440B S44003	0.75 ~ 0.95	16.0 ~ 18.0	≤0.75	-	-	1	1	0.04	0.03
Europe EN	X90CrMoV18 1.4112	0.85 ~ 0.95	17.0 ~ 19.0	0.90 ~ 1.30	0.07 ~ 0.12	-	1	1	0.04	0.015

2. Hot Forging Process of 9Cr18MoV(90Cr18MoV)

Special attention should be paid to the hot working process of 90Cr18MoV (9Cr18MoV) steel. It is recommended to use a cold-charged furnace for heating, with a heating rate that should not be too fast, especially below 700°C. Additionally, the final forging temperature should be maintained at a higher level, and strict attention should be paid to the cooling conditions.

Item	Temperatura de aquecimento/°C	Initial Forging Temp./°C	Final Forging Temp./°C	Método de resfriamento
Lingote de aço	1130 ~ 1150	1080 ~ 1100	850 ~ 900	Sand Cooling
Tarugo de aço	1100 ~ 1120	1050 ~ 1080	850 ~ 900	Sand Cooling

3. Tratamento térmico of 9Cr18MoV(90Cr18MoV)

The heat treatment procedure is as follows:

1. Recozimento:
   • Temperatura: 850 ~ 870°C
   • Tempo de imersão: 4 ~ 6 hours
   • Resfriamento: Furnace cool to below 600°C before discharging.
   • Post-Annealing Hardness: ≤269 HBW
2. Recrystallization Annealing:
   • Heating Temperature: 730 ~ 750°C
   • Resfriamento: Ar fresco.

4. Quenching and Tempering

• Têmpera:
  • Temperatura de austenitização: 1050 ~ 1070°C
  • Meio de têmpera: Óleo
  • Dureza após têmpera: ≥58 HRC
• Têmpera:
  • Temperatura de têmpera: 160 ~ 180°C
  • Tempo de imersão: 3 ~ 5 hours
  • Final Hardness: ≥58 HRC